Key Points
-
Gephyrin is a multifunctional protein that is responsible for molybdenum cofactor biosynthesis in all organisms and for postsynaptic clustering of glycine receptors and type A GABA receptors in the vertebrate CNS.
-
Gephyrin self-assembles to form a protein scaffold, which interacts with numerous, structurally different proteins to form a highly ordered signalling complex in glycinergic and GABAergic synapses.
-
Gephyrin's function as a scaffolding protein is regulated by alternative mRNA splicing and by multiple post-transcriptional and post-translational modifications, which are only beginning to be understood.
-
Regulation of the gephyrin scaffold by multiple signalling cascades modulates the formation and plasticity of GABAergic synapses and thereby the strength of GABAergic transmission.
-
Because signals impinging on gephyrin post-translational modification are activated by excitatory neurotransmission and increased intracellular calcium concentration, the gephyrin scaffold may form an intracellular hub that modulates synaptic homeostasis and excitatory–inhibitory balance.
-
Abnormal GABAergic transmission during brain development, possibly brought about or at least linked to impaired gephyrin regulation, might have enduring structural and functional consequences in the adult brain and might contribute to the pathophysiology of major neurological and neuropsychiatric diseases.
Abstract
The neurotransmitters GABA and glycine mediate fast synaptic inhibition by activating ligand-gated chloride channels — namely, type A GABA (GABAA) and glycine receptors. Both types of receptors are anchored postsynaptically by gephyrin, which self-assembles into a scaffold and interacts with the cytoskeleton. Current research indicates that postsynaptic gephyrin clusters are dynamic assemblies that are held together and regulated by multiple protein–protein interactions. Moreover, post-translational modifications of gephyrin regulate the formation and plasticity of GABAergic synapses by altering the clustering properties of postsynaptic scaffolds and thereby the availability and function of receptors and other signalling molecules. Here, we discuss the formation and regulation of the gephyrin scaffold, its role in GABAergic and glycinergic synaptic function and the implications for the pathophysiology of brain disorders caused by abnormal inhibitory neurotransmission.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Filamin A organizes γ‑aminobutyric acid type B receptors at the plasma membrane
Nature Communications Open Access 03 January 2023
-
Multivalent binding kinetics resolved by fluorescence proximity sensing
Communications Biology Open Access 07 October 2022
-
Complex regulation of Gephyrin splicing is a determinant of inhibitory postsynaptic diversity
Nature Communications Open Access 18 June 2022
Access options
Subscribe to this journal
Receive 12 print issues and online access
$189.00 per year
only $15.75 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout



References
Ogino, K. et al. Duplicated gephyrin genes showing distinct tissue distribution and alternative splicing patterns mediate molybdenum cofactor biosynthesis, glycine receptor clustering, and escape behavior in zebrafish. J. Biol. Chem. 286, 806–817 (2011).
Fritschy, J. M., Harvey, R. J. & Schwarz, G. Gephyrin, where do we stand, where do we go? Trends Neurosci. 31, 257–264 (2008).
Tretter, V. et al. Gephyrin, the enigmatic organizer at GABAergic synapses. Front. Cell. Neurosci. 6, 23 (2012).
Dutertre, S., Becker, C. M. & Betz, H. Inhibitory glycine receptors: an update. J. Biol. Chem. 287, 40216–40223 (2012).
Marín, O. Interneuron dysfunction in psychiatric disorders. Nature Rev. Neurosci. 13, 107–120 (2012).
Lewis, D. A. Cortical circuit dysfunction and cognitive deficits in schizophrenia — implications for preemptive interventions. Eur. J. Neurosci. 35, 1871–1878 (2012).
Nawrotzki, R., Islinger, M., Vogel, I., Völkl, A. & Kirsch, J. Expression and subcellular distribution of gephyrin in non-neuronal tissues and cells. Histochem. Cell Biol. 137, 471–482 (2012).
Schwarz, G., Mendel, R. R. & Ribbe, M. W. Molybdenum cofactors, enzymes and pathways. Nature 460, 839–847 (2009).
Stallmeyer, B. et al. The neurotransmitter receptor-anchoring protein gephyrin reconstitutes molybdenum cofactor biosynthesis in bacteria, plants, and mammalian cells. Proc. Natl Acad. Sci. USA 96, 1333–1338 (1999).
Feng, G. et al. Dual requirement for gephyrin in glycine receptor clustering and molybdoenzyme activity. Science 282, 1321–1324 (1998). This paper describes the effects of targeted deletion of Gphn in mice, revealing gephyrin's dual function in molybdenum cofactor biosynthesis and postsynaptic clustering of GlyRs and GABA A Rs at inhibitory synapses.
Reiss, J. et al. A GPHN point mutation leading to molybdenum cofactor deficiency. Clin. Genet. 80, 598–599 (2011).
Smolinsky, B., Eichler, S. A., Buchmeier, S., Meier, J. C. & Schwarz, G. Splice-specific functions of gephyrin in molybdenum cofactor biosynthesis. J. Biol. Chem. 283, 17370–17379 (2008).
Pfeiffer, F., Graham, D. & Betz, H. Purification by affinity chromatography of the glycine receptor of rat spinal cord. J. Biol. Chem. 257, 9389–9393 (1982).
Kirsch, J. et al. The 93-kDa glycine receptor-associated protein binds to tubulin. J. Biol. Chem. 266, 22242–22245 (1991).
Pfeiffer, F., Simler, R., Grenningloh, G. & Betz, H. Monoclonal antibodies and peptide mapping reveal structural similarities between the subunits of the glycine receptor of rat spinal cord. Proc. Natl Acad. Sci. USA 81, 7224–7227 (1984).
Triller, A., Cluzeaud, F., Pfeiffer, F., Betz, H. & Korn, H. Distribution of glycine receptors at central synapses: an immunoelectron microscopy study. J. Cell Biol. 101, 683–688 (1985).
Triller, A., Cluzeaud, F. & Korn, H. γ-Aminobutyric acid-containing terminals can be apposed to glycine receptors at central synapses. J. Cell Biol. 104, 947–956 (1987).
Bohlhalter, S., Mohler, H. & Fritschy, J. M. Inhibitory neurotransmission in rat spinal cord: co-localization of glycine and GABAA-receptors at GABAergic synaptic contacts demonstrated by triple-immunofluorescence staining. Brain Res. 642, 59–69 (1994).
Sassoè-Pognetto, M. et al. Colocalization of gephyrin and GABAA-receptor subunits in the rat retina. J. Comp. Neurol. 357, 1–14 (1995).
Giustetto, M., Kirsch, J., Fritschy, J. M., Cantino, D. & Sassoè-Pognetto, M. Localisation of the clustering protein gephyrin at GABAergic synapses in the main olfactory bulb of the rat. J. Comp. Neurol. 395, 231–244 (1998).
Sassoè-Pognetto, M., Panzanelli, P., Sieghart, W. & Fritschy, J. M. Co-localization of multiple GABAA receptor subtypes with gephyrin at postsynaptic sites. J. Comp. Neurol. 420, 481–498 (2000). This paper provides the first anatomical demonstration of the presence of gephyrin clusters in the PSD of GABAergic synapses in major regions of the CNS, in which it was associated with GABA A R subtypes containing the α1-, α2- or α3-subunit.
Lardi-Studler, B. et al. Vertebrate-specific sequences in the gephyrin E-domain regulate cytosolic aggregation and postsynaptic clustering. J. Cell Biol. 120, 1371–1382 (2007).
Kneussel, M. & Loebrich, S. Trafficking and synaptic anchoring of ionotropic inhibitory neurotransmitter receptors. Biol. Cell 99, 297–309 (2007).
Papadopoulos, T. & Soykan, T. The role of collybistin in gephyrin clustering at inhibitory synapses: facts and open questions. Front. Cell. Neurosci. 5, 11 (2011).
Sassoè-Pognetto, M., Frola, E., Pregno, G., Briatore, F. & Patrizi, A. Understanding the molecular diversity of GABAergic synapses. Front. Cell. Neurosci. 5, 4 (2011).
Kirsch, J., Kuhse, J. & Betz, H. Targeting of glycine receptor subunits to gephyrin-rich domains in transfected human embryonic kidney cells. Mol. Cell. Neurosci. 6, 450–461 (1995).
Dumoulin, A., Triller, A. & Kneussel, M. Cellular transport and membrane dynamics of the glycine receptor. Front. Mol. Neurosci. 2, 28 (2010).
Barnard, E. A. et al. International Union of Pharmacology. XV. Subtypes of γ-aminobutyric acidA receptors: classification on the basis of subunit structure and function. Pharmacol. Rev. 50, 291–313 (1998).
Durisic, N. et al. Stoichiometry of the human glycine receptor revealed by direct subunit counting. J. Neurosci. 32, 12915–12920 (2012).
Grudzinska, J. et al. The β subunit determines the ligand binding properties of synaptic glycine receptors. Neuron 45, 727–739 (2005).
Yang, Z., Taran, E., Webb, T. & Lynch, J. Stoichiometry and subunit arrangement of α1β glycine receptors as determined by atomic force microscopy. Biochemistry 51, 5229–5231 (2012).
Kirsch, J., Wolters, I., Triller, A. & Betz, H. Gephyrin antisense oligonucleotides prevent glycine receptor clustering in spinal neurons. Nature 366, 745–748 (1993).
Meyer, G., Kirsch, J., Betz, H. & Langosch, D. Identification of a gephyrin binding motif on the glycine receptor β subunit. Neuron 15, 563–572 (1995).
Hanus, C., Vannier, C. & Triller, A. Intracellular association of glycine receptor with gephyrin increases its plasma membrane accumulation rate. J. Neurosci. 24, 1119–1128 (2004).
Maas, C. et al. Neuronal cotransport of glycine receptor and the scaffold protein gephyrin. J. Cell Biol. 172, 441–451 (2006).
Tretter, V. et al. The clustering of GABAA receptor subtypes at inhibitory synapses is facilitated via the direct binding of receptor α2 subunits to gephyrin. J. Neurosci. 28, 1356–1365 (2008). This paper provides the first biochemical evidence for a direct interaction between gephyrin and a GABA A R subunit, α2, and shows that it determines the localization of these receptors in specific subpopulations of GABAergic synapses in pyramidal cells.
Tretter, V. et al. Molecular basis of the GABAA receptor α3 subunit interaction with gephyrin. J. Biol. Chem. 286, 37702–37711 (2011).
Mukherjee, J. et al. The residence time of GABAARs at inhibitory synapses is determined by direct binding of the receptor α1 subunit to gephyrin. J. Neurosci. 31, 14677–14687 (2011).
Kowalczyk, S. et al. Direct binding of GABAA receptor β2 and β3 subunits to gephyrin. Eur. J. Neurosci. 37, 544–554 (2013).
Maric, H. M., Mukherjee, J., Tretter, V., Moss, S. J. & Schindelin, H. Gephyrin-mediated GABAA and glycine receptor clustering relies on a common binding site. J. Biol. Chem. 286, 42105–42114 (2011).
Brünig, I., Scotti, E., Sidler, C. & Fritschy, J. M. Intact sorting, targeting, and clustering of γ-aminobutyric acid A receptor subtypes in hippocampal neurons in vitro. J. Comp. Neurol. 443, 43–45 (2002).
Kralic, J. E. et al. Compensatory alteration of inhibitory synaptic circuits in thalamus and cerebellum of GABAA receptor α1 subunit knockout mice. J. Comp. Neurol. 495, 408–421 (2006).
Panzanelli, P. et al. Distinct mechanisms regulate GABAA receptor and gephyrin clustering at perisomatic and axo-axonic synapses on CA1 pyramidal cells. J. Physiol. 589, 4959–4980 (2011).
Crestani, F. et al. Trace fear conditioning involves hippocampal α5 GABAA receptors. Proc. Natl Acad. Sci. USA 99, 8980–8985 (2002).
Peng, Z. et al. GABAA receptor changes in δ subunit-deficient mice: altered expression of α4 and γ2 subunits in the forebrain. J. Comp. Neurol. 446, 179–197 (2002).
Gunther, U. et al. Benzodiazepine-insensitive mice generated by targeted disruption of the γ2-subunit gene of γ-aminobutyric acid type A receptors. Proc. Natl Acad. Sci. USA 92, 7749–7753 (1995).
Fischer, F. et al. Reduced synaptic clustering of GABA and glycine receptors in the retina of the gephyrin null mutant mouse. J. Comp. Neurol. 427, 634–648 (2000).
Kneussel, M. et al. Gephyrin-independent clustering of postsynaptic GABAA receptor subtypes. Mol. Cell. Neurosci. 17, 973–982 (2001).
Levi, S., Logan, S. M., Tovar, K. R. & Craig, A. M. Gephyrin is critical for glycine receptor clustering but not for the formation of functional GABAergic synapses in hippocampal neurons. J. Neurosci. 24, 207–217 (2004).
Lagier, S. et al. GABAergic inhibition at dendrodendritic synapses tunes gamma oscillations in the olfactory bulb. Proc. Natl Acad. Sci. USA 104, 7259–7264 (2007).
Peden, D. R. et al. Developmental maturation of synaptic and extrasynaptic GABAA receptors in mouse thalamic ventrobasal neurones. J. Physiol. 586, 965–987 (2008).
Fritschy, J. M., Panzanelli, P., Kralic, J. E., Vogt, K. E. & Sassoè-Pognetto, M. Differential dependence of axo-dendritic and axo-somatic GABAergic synapses on GABAA receptors containing the α1 subunit in Purkinje cells. J. Neurosci. 26, 3245–3255 (2006). This paper demonstrates that postsynaptic clustering of gephyrin in GABAergic synapses depends on the presence of GABA A R and shows mistargeting of GABAergic presynaptic terminals to postsynaptic structures that are normally innervated by glutamatergic synapses in the absence of functional GABAergic transmission.
Patrizi, A. et al. Synapse formation and clustering of neuroligin-2 in the absence of GABAA receptors. Proc. Natl Acad. Sci. USA 105, 13151–13156 (2008).
Studer, R. et al. Alteration of GABAergic synapses and gephyrin clusters in the thalamic reticular nucleus of GABAA receptor α3 subunit-null mice. Eur. J. Neurosci. 24, 1307–1315 (2006).
Loebrich, S., Bahring, R., Katsuno, T., Tsukita, S. & Kneussel, M. Activated radixin is essential for GABAA receptor α5 subunit anchoring at the actin cytoskeleton. EMBO J. 25, 987–999 (2006).
Wu, X. et al. GABAA receptor α subunits play a direct role in synaptic versus extrasynaptic targeting. J. Biol. Chem. 287, 27417–27430 (2012).
Knuesel, I. et al. Altered synaptic clustering of GABAA-receptors in mice lacking dystrophin (mdx mice). Eur. J. Neurosci. 11, 4457–4462 (1999).
Sumita, K. et al. Synaptic scaffolding molecule (S-SCAM) membrane-associated guanylate kinase with inverted organization (MAGI)-2 is associated with cell adhesion molecules at inhibitory synapses in rat hippocampal neurons. J. Neurochem. 100, 154–166 (2007).
Fukaya, M. et al. SynArfGEF is a guanine nucleotide exchange factor for Arf6 and localizes preferentially at post-synaptic specializations of inhibitory synapses. J. Neurochem. 116, 1122–1137 (2011).
Fritschy, J. M., Panzanelli, P. & Tyagarajan, S. K. Molecular and functional heterogeneity of GABAergic synapses. Cell. Mol. Life Sci. 69, 2485–2499 (2012).
Graf, E. R., Zhang, X., Jin, S. X., Linhoff, M. W. & Craig, A. M. Neurexins induce differentiation of GABA and glutamate postsynaptic specializations via neuroligins. Cell 119, 1013–1026 (2004).
Scheiffele, P., Fan, J., Choih, J., Fetter, R. & Serafini, T. Neuroligin expressed in nonneuronal cells triggers presynaptic development in contacting axons. Cell 101, 657–669 (2000). References 61 and 62 reveal the powerful synaptogenic action of NLGNs in postsynaptic cells depending on differential trans-interaction with neurexins expressed in presynaptic structures.
Dong, N., Qi, J. S. & Chen, G. Molecular reconstitution of functional GABAergic synapses with expression of neuroligin-2 and GABAA receptors. Mol. Cell. Neurosci. 35, 14–23 (2007).
Hoon, M. et al. Neuroligin-4 is localized to glycinergic postsynapses and regulates inhibition in the retina. Proc. Natl Acad. Sci. USA 108, 3053–3058 (2011).
Varoqueaux, F., Jamain, S. & Brose, N. Neuroligin 2 is exclusively localized to inhibitory synapses. Eur. J. Cell Biol. 83, 449–456 (2004).
Poulopoulos, A. et al. Homodimerization and isoform-specific heterodimerization of neuroligins. Biochem. J. 446, 321–330 (2012).
Budreck, E. C. & Scheiffele, P. Neuroligin-3 is a neuronal adhesion protein at GABAergic and glutamatergic synapses. Eur. J. Neurosci. 26, 1738–1748 (2007).
Baudouin, S. et al. Shared synaptic pathophysiology in syndromic and nonsyndromic rodent models of autism. Sci. Signal. 338, 128–132 (2012).
Giannone, G. et al. Neurexin-1β binding to neuroligin-1 triggers the preferential recruitment of PSD-95 versus gephyrin through tyrosine phosphorylation of neuroligin-1. Cell Rep. 3, 1996–2007 (2013).
Poulopoulos, A. et al. Neuroligin 2 drives postsynaptic assembly at perisomatic inhibitory synapses through gephyrin and collybistin. Neuron 63, 628–642 (2009). This paper reveals a direct interaction between NLGN2 and gephyrin, and proposes a model of how this interaction functionally activates collybistin bound to gephyrin to initiate the formation of GABAergic PSDs and recruit GABA A Rs to these sites.
Varoqueaux, F. et al. Neuroligins determine synapse maturation and function. Neuron 51, 741–754 (2006).
Hoon, M. et al. Neuroligin 2 controls the maturation of GABAergic synapses and information processing in the retina. J. Neurosci. 29, 8039–8050 (2009).
Jedlicka, P. et al. Increased dentate gyrus excitability in neuroligin-2-deficient mice in vivo. Cereb. Cortex 21, 357–367 (2011).
Gibson, J. R., Huber, K. M. & Südhof, T. C. Neuroligin-2 deletion selectively decreases inhibitory synaptic transmission originating from fast-spiking but not from somatostatin-positive interneurons. J. Neurosci. 29, 13883–13897 (2009).
Blundell, J. et al. Increased anxiety-like behavior in mice lacking the inhibitory synapse cell adhesion molecule neuroligin 2. Genes Brain Behav. 8, 114–126 (2009).
Wöhr, M. et al. Developmental delays and reduced pup ultrasonic vocalizations but normal sociability in mice lacking the postsynaptic cell adhesion protein neuroligin2. Behav. Brain Res. 251, 50–64 (2013).
Kins, S., Betz, H. & Kirsch, J. Collybistin, a newly identified brain-specific GEF, induces submembrane clustering of gephyrin. Nature Neurosci. 3, 22–29 (2000). This paper reports the identification of collybistin as a RHO GEF that directly interacts with gephyrin and is required for the translocation of gephyrin towards the plasma membrane of non-neuronal cells.
Miller, M. B., Yan, Y., Eipper, B. A. & Mains, R. E. Neuronal Rho GEFs in synaptic physiology and behavior. Neuroscientist 19, 255–273 (2013).
Xiang, S. et al. The crystal structure of Cdc42 in complex with collybistin II, a gephyrin-interacting guanine nucleotide exchange factor. J. Mol. Biol. 359, 35–46 (2006).
Harvey, K. et al. The GDP-GTP exchange factor collybistin: an essential determinant of neuronal gephyrin clustering. J. Neurosci. 24, 5816–5826 (2004). This paper characterizes major collybistin splice variants and demonstrates the key role of collybistin in gephyrin clustering at GABAergic PSDs.
Grosskreutz, Y. et al. Identification of a gephyrin-binding motif in the GDP/GTP exchange factor collybistin. Biol. Chem. 382, 1455–1462 (2001).
Kalscheuer, V. M. et al. A balanced chromosomal translocation disrupting ARHGEF9 is associated with epilepsy, anxiety, aggression, and mental retardation. Hum. Mutat. 30, 61–68 (2009).
Körber, C. et al. Effects of distinct collybistin isoforms on the formation of GABAergic synapses in hippocampal neurons. Mol. Cell. Neurosci. 50, 250–259 (2012).
Chiou, T. T. et al. Differential regulation of the postsynaptic clustering of γ-aminobutyric acid type A (GABAA) receptors by collybistin isoforms. J. Biol. Chem. 286, 22456–22468 (2011).
Tyagarajan, S. K., Ghosh, H., Harvey, K. & Fritschy, J. M. Collybistin splice variants differentially interact with gephyrin and Cdc42 to regulate gephyrin clustering at GABAergic synapses. J. Cell Sci. 124, 2786–2796 (2011).
Patrizi, A. et al. Selective localization of collybistin at a subset of inhibitory synapses in brain circuits. J. Comp. Neurol. 520, 130–141 (2011).
Papadopoulos, T. et al. Impaired GABAergic transmission and altered hippocampal synaptic plasticity in collybistin-deficient mice. EMBO J. 26, 3888–3899 (2007). This paper reveals that targeted deletion of Arhgef9 , the gene encoding collybistin, has no effect at glycinergic synapses, whereas it impairs gephyrin and GABA A R clustering in a cell-specific manner across the CNS, affecting synaptic plasticity and anxiety-like behaviour.
Papadopoulos, T. et al. Collybistin is required for both the formation and maintenance of GABAergic postsynapses in the hippocampus. Mol. Cell. Neurosci. 39, 161–169 (2008).
Nakajima, K. et al. Molecular motor KIF5A is essential for GABAA receptor transport, and KIF5A deletion causes epilepsy. Neuron 76, 945–961 (2012).
O'Sullivan, G. A., Kneussel, M., Elazar, Z. & Betz, H. GABARAP is not essential for GABA receptor targeting to the synapse. Eur. J. Neurosci. 22, 2644–2648 (2005).
Twelvetrees, A. et al. Delivery of GABAARs to synapses is mediated by HAP1-KIF5 and disrupted by mutant huntingtin. Neuron 65, 53–65 (2010).
Meier, J. & Grantyn, R. A gephyrin-related mechanism restraining glycine receptor anchoring at GABAergic synapses. J. Neurosci. 24, 1398–1405 (2004).
Kirsch, J. & Betz, H. The postsynaptic localization of the glycine receptor-associated protein gephyrin is regulated by the cytoskeleton. J. Neurosci. 15, 4148–4156 (1995).
Charrier, C., Ehrensperger, M. V., Dahan, M., Lévi, S. & Triller, A. Cytoskeleton regulation of glycine receptor number at synapses and diffusion in the plasma membrane. J. Neurosci. 26, 8502–8511 (2006).
van Zundert, B. et al. Glycine receptors involved in synaptic transmission are selectively regulated by the cytoskeleton in mouse spinal neurons. J. Neurophysiol. 87, 640–644 (2002).
Allison, D. W., Chervin, A. S., Gelfand, W. I. & Craig, A. M. Postsynaptic scaffolds of excitatory and inhibitory synapses in hippocampal neurons: maintenance of core components independent of actin filaments and microtubules. J. Neurosci. 20, 4545–4554 (2000).
Maas, C. et al. Synaptic activation modifies microtubules underlying transport of postsynaptic cargo. Proc. Natl Acad. Sci. USA 106, 8731–8736 (2009).
Moreno-Lopez, B., de la Cruz, R. R., Pastor, A. M., Delgado-Garcia, J. M. & Alvarez, F. J. Effects of botulinum neurotoxin type A on the expression of gephyrin in cat abducens motoneurons. J. Comp. Neurol. 400, 1–17 (1998).
Giesemann, T. et al. Complex formation between the postsynaptic scaffolding protein gephyrin, profilin, and Mena: a possible link to the microfilament system. J. Neurosci. 23, 8330–8339 (2003).
Mammoto, A. et al. Interactions of drebrin and gephyrin with profilin. Biochem. Biophys. Res. Commun. 243, 86–89 (1998).
Murk, K. et al. Neuronal profilin isoforms are addressed by different signalling pathways. PLoS ONE 7, e34167 (2012).
Witke, W. et al. In mouse brain profilin I and profilin II associate with regulators of the endocytic pathway and actin assembly. EMBO J. 16, 967–976 (1998).
Smith, K. et al. Stabilization of GABAA receptors at endocytic zones is mediated by an AP2 binding motif within the GABAA receptor β3 subunit. J. Neurosci. 32, 2485–2498 (2012).
Heisler, F. et al. Muskelin regulates actin filament- and microtubule-based GABAA receptor transport in neurons. Neuron 70, 66–81 (2011).
Huang, R., He, S., Chen, Z., Dillon, G. & Leidenheimer, N. Mechanisms of homomeric α1 glycine receptor endocytosis. Biochemistry 46, 11484–11493 (2007).
Fuhrmann, J. C. et al. Gephyrin interacts with dynein light chains 1 and 2, components of motor protein complexes. J. Neurosci. 22, 5393–5402 (2002).
Jaffrey, S. R. & Snyder, S. H. PIN: an associated protein inhibitor of neuronal nitric oxide synthase. Science 274, 774–777 (1996).
Szabadits, E. et al. NMDA receptors in hippocampal GABAergic synapses and their role in nitric oxide signaling. J. Neurosci. 31, 5893–5904 (2011).
Szabadits, E. et al. Hippocampal GABAergic synapses possess the molecular machinery for retrograde nitric oxide signaling. J. Neurosci. 27, 8101–8111 (2007).
Specht, C. et al. Quantitative nanoscopy of inhibitory synapses: counting gephyrin molecules and receptor binding sites. Neuron 79, 308–321 (2013). This paper reports the quantitative analysis of gephyrin, GABA A Rs and GlyRs in inhibitory synapses in vitro and in vivo using supra-resolution microscopy. Distinct differences in clustering density and regulation are reported between the two types of synapses.
Renner, M., Schweizer, C., Bannai, H., Triller, A. & Lévi, S. Diffusion barriers constrain receptors at synapses. PLoS ONE 7, e43032 (2012).
Bannai, H. et al. Activity-dependent tuning of inhibitory neurotransmission based on GABAAR diffusion dynamics. Neuron 62, 670–682 (2009).
Calamai, M. et al. Gephyrin oligomerization controls GlyR mobility and synaptic clustering. J. Neurosci. 29, 7639–7648 (2009).
Specht, C. G. et al. Regulation of glycine receptor diffusion properties and gephyrin interactions by protein kinase C. EMBO J. 30, 3842–3853 (2011).
Charrier, C. et al. A crosstalk between β1 and β3 integrins controls glycine receptor and gephyrin trafficking at synapses. Nature Neurosci. 13, 1388–1395 (2010).
Kneussel, M. & Betz, H. Receptors, gephyrin and gephyrin-associated proteins: novel insights into the assembly of inhibitory postsynaptic membrane specializations. J. Physiol. 525, 1–9 (2000).
Kneussel, M. & Betz, H. Clustering of inhibitory neurotransmitter receptors at developing postsynaptic sites: the membrane activation model. Trends Neurosci. 23, 429–435 (2000).
Machado, P. et al. Heat shock cognate protein 70 regulates gephyrin clustering. J. Neurosci. 31, 3–14 (2011).
Saiepour, L. et al. Complex role of collybistin and gephyrin in GABAA receptor clustering. J. Biol. Chem. 285, 29623–29631 (2010).
Reddy-Alla, S. et al. PH-domain-driven targeting of collybistin but not Cdc42 activation is required for synaptic gephyrin clustering. Eur. J. Neurosci. 31, 1173–1184 (2010).
Klausberger, T. & Somogyi, P. Neuronal diversity and temporal dynamics: the unity of hippocampal circuit operations. Science 321, 53–57 (2008).
Shipman, S. L. & Nicoll, R. A. Dimerization of postsynaptic neuroligin drives synaptic assembly via transsynaptic clustering of neurexin. Proc. Natl Acad. Sci. USA 109, 19432–19437 (2012).
Pettem, K. L., Yokomaku, D., Takahashi, H., Ge, Y. & Craig, A. M. Interaction between autism-linked MDGAs and neuroligins suppresses inhibitory synapse development. J. Cell Biol. 200, 321–336 (2013).
Lee, K. et al. MDGAs interact selectively with neuroligin-2 but not other neuroligins to regulate inhibitory synapse development. Proc. Natl Acad. Sci. USA 110, 336–341 (2013).
Tyagarajan, S. K. et al. Regulation of GABAergic synapse formation and plasticity by GSK3β-dependent phosphorylation of gephyrin. Proc. Natl Acad. Sci. USA 108, 379–384 (2011). This paper reports the identification of gephyrin residue Ser270 as a target for GSK3β-mediated phosphorylation to regulate the density of GABAergic synapses and the frequency of miniature inhibitory postsynaptic currents in vitro , which also requires activation of the calcium-dependent protein calpain.
Kuhse, J. et al. Phosphorylation of gephyrin in hippocampal neurons by cyclin-dependent kinase CDK5 at Ser-270 is dependent on collybistin. J. Biol. Chem. 287, 30952–30966 (2012).
Frola, E. et al. Synaptic competition sculpts the development of GABAergic axo-dendritic but not perisomatic synapses. PLoS ONE 8, e56311 (2013).
Chen, A. et al. TrkB (tropomyosin-related kinase B) controls the assembly and maintenance of GABAergic synapses in the cerebellar cortex. J. Neurosci. 31, 2769–2780 (2011).
Takahashi, H. et al. Selective control of inhibitory synapse development by Slitrk3–PTPδ trans-synaptic interaction. Nature Neurosci. 15, 389–398 (2012).
Chiu, C. et al. Compartmentalization of GABAergic inhibition by dendritic spines. Sci. Signal. 340, 759–762 (2013).
Chen, J. et al. Clustered dynamics of inhibitory synapses and dendritic spines in the adult neocortex. Neuron 74, 361–373 (2012). This paper reports rapid structural changes, which were visualized by two-photon imaging in vivo , that affect both GABAergic and glutamatergic synapses on cortical neurons and that are modulated by monocular deprivation in adult mice.
Woo, J. et al. The adhesion protein IgSF9b is coupled to neuroligin 2 via S-SCAM to promote inhibitory synapse development. J. Cell Biol. 201, 929–944 (2013).
Tyagarajan, S. et al. Extracellular signal-regulated kinase and glycogen synthase kinase 3β regulate gephyrin postsynaptic aggregation and GABAergic synaptic function in a calpain-dependent mechanism. J. Biol. Chem. 288, 9634–9647 (2013).
Fang, C. et al. GODZ-mediated palmitoylation of GABAA receptors is required for normal assembly and function of GABAergic inhibitory synapses. J. Neurosci. 26, 12758–12768 (2006).
Arancibia-Cárcamo, I. et al. Ubiquitin-dependent lysosomal targeting of GABAA receptors regulates neuronal inhibition. Proc. Natl Acad. Sci. USA 106, 17552–17557 (2009).
Luscher, B., Fuchs, T. & Kilpatrick, C. L. GABAA receptor trafficking-mediated plasticity of inhibitory synapses. Neuron 70, 385–409 (2011).
Lushnikova, I., Skibo, G., Muller, D. & Nikonenko, I. Excitatory synaptic activity is associated with a rapid structural plasticity of inhibitory synapses on hippocampal CA1 pyramidal cells. Neuropharmacology 60, 757–764 (2011).
Niwa, F. et al. Gephyrin-independent GABAAR mobility and clustering during plasticity. PLoS ONE 7, e36148 (2012).
van Versendaal, D. et al. Elimination of inhibitory synapses is a major component of adult ocular dominance plasticity. Neuron 74, 374–383 (2012).
Rui, Y. et al. Activity-dependent regulation of dendritic growth and maintenance by glycogen synthase kinase 3β. Nature Commun. 4, 2628 (2013).
Castillo, P., Chiu, C. & Carroll, R. Long-term plasticity at inhibitory synapses. Curr. Opin. Neurobiol. 21, 328–338 (2011).
Inoue, W. et al. Noradrenaline is a stress-associated metaplastic signal at GABA synapses. Nature Neurosci. 16, 605–612 (2013).
Kullmann, D., Moreau, A., Bakiri, Y. & Nicholson, E. Plasticity of inhibition. Neuron 75, 951–962 (2012).
Marsden, K. C., Beattie, J. B., Friedenthal, J. & Carroll, R. C. NMDA receptor activation potentiates inhibitory transmission through GABA receptor-associated protein-dependent exocytosis of GABAA receptors. J. Neurosci. 27, 14326–14337 (2007).
Muir, J. et al. NMDA receptors regulate GABAA receptor lateral mobility and clustering at inhibitory synapses through serine 327 on the γ2 subunit. Proc. Natl Acad. Sci. USA 107, 16679–16684 (2010).
Gross, G. et al. Recombinant probes for visualizing endogenous synaptic proteins in living neurons. Neuron 78, 971–985 (2013).
Pallotto, M. et al. Early formation of GABAergic synapses governs the development of adult-born neurons in the olfactory bulb. J. Neurosci. 32, 9103–9115 (2012).
Reiss, J. et al. A mutation in the gene for the neurotransmitter receptor-clustering protein gephyrin causes a novel form of molybdenum cofactor deficiency. Am. J. Hum. Genet. 68, 208–213 (2001).
Butler, M. et al. Autoimmunity to gephyrin in Stiff-Man syndrome. Neuron 26, 307–312 (2000).
Rees, M. I. et al. Isoform heterogeneity of the human gephyrin gene (GPHN), binding domains to the glycine receptor, and mutation analysis in hyperekplexia. J. Biol. Chem. 278, 24688–24696 (2003).
Grosskreutz, Y., Betz, H. & Kneussel, M. Rescue of molybdenum cofactor biosynthesis in gephyrin-deficient mice by a Cnx1 transgene. Biochem. Biophys. Res. Com. 301, 450–455 (2003).
Harvey, R. J., Topf, M., Harvey, K. & Rees, M. I. The genetics of hyperekplexia: more than startle! Trends Genet. 24, 439–447 (2008).
Förstera, B. et al. Irregular RNA splicing curtails postsynaptic gephyrin in the cornu ammonis of patients with epilepsy. Brain 133, 3778–3794 (2010).
Möhler, H. The GABA system in anxiety and depression and its therapeutic potential. Neuropharmacology 62, 42–53 (2012).
Rudolph, U. & Möhler, H. GABAA receptor subtypes: therapeutic potential in Down syndrome, affective disorders, schizophrenia, and autism. Annu. Rev. Pharmacol. Toxicol. 54, 483–507 (2014).
Shen, Q., Fuchs, T., Sahir, N. & Luscher, B. GABAergic control of critical developmental periods for anxiety- and depression-related behavior in mice. PLoS ONE 7, e47441 (2012).
Luscher, B., Shen, Q. & Sahir, N. The GABAergic deficit hypothesis of major depressive disorder. Mol. Psychiatry 16, 383–406 (2011).
Chattopadhyaya, B. et al. Experience and activity-dependent maturation of perisomatic GABAergic innervation in primary visual cortex during a postnatal critical period. J. Neurosci. 24, 9598–9611 (2004).
Coghlan, S. et al. GABA system dysfunction in autism and related disorders: from synapse to symptoms. Neurosci. Biobehav. Rev. 36, 2044–2055 (2012).
Paluszkiewicz, S., Martin, B. & Huntsman, M. Fragile X syndrome: the GABAergic system and circuit dysfunction. Dev. Neurosci. 33, 349–364 (2011).
Lin, Y. et al. Activity-dependent regulation of inhibitory synapse development by Npas4. Nature 455, 1198–1204 (2008).
Belaidi, A. & Schwarz, G. Metal insertion into the molybdenum cofactor: product-substrate channelling demonstrates the functional origin of domain fusion in gephyrin. Biochem. J. 450, 149–157 (2013).
Paarmann, I., Schmitt, B., Meyer, B., Karas, M. & Betz, H. Mass spectrometric analysis of glycine receptor-associated gephyrin splice variants. J. Biol. Chem. 281, 34918–34925 (2006).
Bedet, C. et al. Regulation of gephyrin assembly and glycine receptor synaptic stability. J. Biol. Chem. 281, 30046–30056 (2006).
Saiyed, T. et al. Molecular basis of gephyrin clustering at inhibitory synapses: role of G- and E-domain interactions. J. Biol. Chem. 282, 5625–5632 (2007).
Prior, P. et al. Primary structure and alternative splice variants of gephyrin, a putative glycine receptor-tubulin linker protein. Neuron 8, 1161–1170 (1992). This paper provides the first detailed analysis of gephyrin splice variants and their domain structure, providing the basis for analysing their function and regulation in the CNS.
David-Watine, B. The human gephyrin (GPHN) gene: structure, chromosome localization and expression in non-neuronal cells. Gene 271, 239–245 (2001).
Schwarz, G., Schrader, N., Mendel, R. R., Hecht, H. J. & Schindelin, H. Crystal structures of human gephyrin and plant Cnx1 G domains: comparative analysis and functional implications. J. Mol. Biol. 312, 405–418 (2001).
Sola, M., Kneussel, M., Heck, I. S., Betz, H. & Weissenhorn, W. X-ray crystal structure of the trimeric N-terminal domain of gephyrin. J. Biol. Chem. 276, 25294–25301 (2001). References 168 and 169 report the crystal structure of the gephyrin G domain and thereby provide insight into its function in molybdenum cofactor biosynthesis and as a scaffolding protein at inhibitory synapses.
Schrader, N. et al. Biochemical characterization of the high affinity binding between the glycine receptor and gephyrin. J. Biol. Chem. 279, 18733–18741 (2004).
Kim, E. Y. et al. Deciphering the structural framework of glycine receptor anchoring by gephyrin. EMBO J. 25, 1385–1395 (2006).
Sola, M. et al. Structural basis of dynamic glycine receptor clustering by gephyrin. EMBO J. 23, 2510–2519 (2004).
Herweg, J. & Schwarz, G. Splice-specific glycine receptor binding, folding, and phosphorylation of the scaffolding protein gephyrin. J. Biol. Chem. 287, 12645–12656 (2012).
Sander, B. et al. Structural characterization of gephyrin by AFM and SAXS reveals a mixture of compact and extended states. Acta Crystallogr. D Biol. Crystallogr. 69, 2050–2060 (2013).
Demirkan, G., Yu, K., Boylan, J. M., Salomon, A. R. & Gruppuso, P. A. Phosphoproteomic profiling of in vivo signaling in liver by the mammalian target of rapamycin complex 1 (mTORC1). PLoS ONE 6, e21729 (2011).
Zita, M. M. et al. Post-phosphorylation prolyl isomerisation of gephyrin represents a mechanism to modulate glycine receptors function. EMBO J. 26, 1761–1771 (2007).
Huttlin, E. et al. A tissue-specific atlas of mouse protein phosphorylation and expression. Cell 143, 1174–1189 (2010).
Wuchter, J. et al. A comprehensive small interfering RNA screen identifies signaling pathways required for gephyrin clustering. J. Neurosci. 32, 14821–14834 (2012).
Bausen, M., Weltzien, F., Betz, H. & O'Sullivan, G. A. Regulation of postsynaptic gephyrin cluster size by protein phosphatase 1. Mol. Cell. Neurosci. 44, 201–209 (2010).
Kang, R. et al. Neural palmitoyl-proteomics reveals dynamic synaptic palmitoylation. Nature 456, 904–909 (2008).
Schwer, B. et al. Calorie restriction alters mitochondrial protein acetylation. Aging Cell 8, 604–606 (2009).
Choudhary, C. et al. Lysine acetylation targets protein complexes and co-regulates major cellular functions. Science 325, 834–840 (2009).
Scheschonka, A., Tang, Z. & Betz, H. Sumoylation in neurons: nuclear and synaptic roles? Trends Neurosci. 30, 85–91 (2007).
Wilkinson, K., Nakamura, Y. & Henley, J. Targets and consequences of protein SUMOylation in neurons. Brain Res. Rev. 64, 195–212 (2010).
Chamberlain, S. et al. SUMOylation and phosphorylation of GluK2 regulate kainate receptor trafficking and synaptic plasticity. Nature Neurosci. 15, 845–852 (2012).
Jaafari, N. et al. SUMOylation is required for glycine-induced increases in AMPA receptor surface expression (ChemLTP) in hippocampal neurons. PLoS ONE 8, e52345 (2013).
Tyagarajan, S. K. et al. Proteins involved in the SUMO pathway modulate gephyrin scaffolding and GABAergic transmission. Soc. Neurosci. Abstr. 745.12 (2012).
Zadran, S. et al. Brain-derived neurotrophic factor and epidermal growth factor activate neuronal m-calpain via mitogen-activated protein kinase-dependent phosphorylation. J. Neurosci. 30, 1086–1095 (2010).
Puskarjov, M., Ahmad, F., Kaila, K. & Blaesse, P. Activity-dependent cleavage of the K-Cl cotransporter KCC2 mediated by calcium-activated protease calpain. J. Neurosci. 32, 11356–11364 (2012).
Greer, P. & Greenberg, M. From synapse to nucleus: calcium-dependent gene transcription in the control of synapse development and function. Neuron 59, 846–860 (2008).
Ch'ng, T. et al. Activity-dependent transport of the transcriptional coactivator CRTC1 from synapse to nucleus. Cell 150, 207–221 (2012).
Jordan, B., Fernholz, B., Khatri, L. & Ziff, E. Activity-dependent AIDA-1 nuclear signaling regulates nucleolar numbers and protein synthesis in neurons. Nature Neurosci. 10, 427–435 (2007).
Guo, J. U. et al. Neuronal activity modifies the DNA methylation landscape in the adult brain. Nature Neurosci. 14, 1345–1351 (2011).
Schratt, G. microRNAs at the synapse. Nature Rev. Neurosci. 10, 842–849 (2009).
Iijima, T. et al. SAM68 regulates neuronal activity-dependent alternative splicing of neurexin-1. Cell 147, 1601–1614 (2011).
Cajigas, I. et al. The local transcriptome in the synaptic neuropil revealed by deep sequencing and high-resolution imaging. Neuron 74, 453–466 (2012). This paper reports the characterization of over 2,500 mRNA transcripts localized in axons or dendrites of the hippocampus neuropile, which encode, among others, numerous synaptic molecules.
Kelleher, R. J., Govindarajan, A. & Tonegawa, S. Translational regulatory mechanisms in persistent forms of synaptic plasticity. Neuron 44, 59–73 (2004).
Paradis, S. et al. An RNAi-based approach identifies molecules required for glutamatergic and GABAergic synapse development. Neuron 53, 217–232 (2007).
Siegel, G. et al. A functional screen implicates microRNA-138-dependent regulation of the depalmitoylation enzyme APT1 in dendritic spine morphogenesis. Nature Cell Biol. 11, 705–716 (2009).
Flavell, S. et al. Genome-wide analysis of MEF2 transcriptional program reveals synaptic target genes and neuronal activity-dependent polyadenylation site selection. Neuron 60, 1022–1038 (2008).
Ramming, M., Betz, H. & Kirsch, J. Analysis of the promoter region of the murine gephyrin gene. FEBS Lett. 405, 137–140 (1997).
Licatalosi, D. et al. HITS-CLIP yields genome-wide insights into brain alternative RNA processing. Nature 456, 464–469 (2008).
Panzanelli, P. et al. Early synapse formation in developing interneurons of the adult olfactory bulb. J. Neurosci. 29, 15039–15052 (2009).
Acknowledgements
This study was supported by the Swiss National Science Foundation. We are grateful to P. Panzanelli (University of Turin, Italy) for the fruitful collaboration and for providing figure 1D.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary information S1 (table)
Gephyrin-interacting molecules (PDF 240 kb)
Supplementary information S2 (figure)
The three domains of gephyrin are indicated by their name (G, C, E). (PDF 184 kb)
Glossary
- Postsynaptic density
-
(PSD). A generic term derived from the ultrastructural appearance of the postsynaptic membrane, which is thicker and more electron-dense than the plasma membrane. This owes to an accumulation of molecules (for example, trans-synaptic extracellular matrix proteins, neurotransmitter receptors and effector proteins) at such regions, which are held together by scaffolding proteins that are bound to the actin cytoskeleton.
- Inhibitory neurotransmission
-
Inhibitory neurotransmission may be mediated by several neurotransmitters, particularly GABA and glycine, which lower the resting membrane potential and increase membrane conductance of neurons by activating ionotropic receptors and, in the case of GABA, reduce excitability of neurons by promoting G protein-mediated activation of voltage-gated potassium and inhibition of calcium channels.
- Post-translational modifications
-
Structural changes (for example, the formation of disulphide bonds between two amino acids) or reversible attachment of functional residues (for example, a phosphate or acetate group), a small protein (for example, ubiquitin or small ubiquitin-related modifier (SUMO)) or a lipid (for example, palmitic acid) to specific residues in a protein, which are mediated by a dedicated enzyme or enzymatic pathway and confer novel properties to the modified protein (for example, functional activation, membrane anchorage or differential targeting).
- Cys-loop ligand-gated ion channels
-
A subfamily of neurotransmitter receptors, comprising the prototypic nicotinic acetylcholine receptor, type A GABA (GABAA) receptors, glycine receptors, and 5-hydroxytryptamine type 3 receptors; these receptors are integral ion channels that mediate fast synaptic transmission and have a pentameric homo- or heteromeric subunit structure.
- Dystroglycan
-
A protein that comprises two non-covalently bound protein products, α-dystroglycan (an extracellular matrix protein) and β-dystroglycan (a transmembrane protein), which are encoded from two exons of DAG1; the proteins products are key constituents of the dystrophin–glycoprotein complex (DGC).
- Protein scaffold
-
A high-order molecular arrangement of proteins, forming a highly structured, crystal-like lattice by self-assembly or through specific protein interaction motives and serving to anchor other proteins (notably neurotransmitter receptors and effector molecules) at specific subcellular sites.
Rights and permissions
About this article
Cite this article
Tyagarajan, S., Fritschy, JM. Gephyrin: a master regulator of neuronal function?. Nat Rev Neurosci 15, 141–156 (2014). https://doi.org/10.1038/nrn3670
Published:
Issue Date:
DOI: https://doi.org/10.1038/nrn3670
This article is cited by
-
Filamin A organizes γ‑aminobutyric acid type B receptors at the plasma membrane
Nature Communications (2023)
-
Multivalent binding kinetics resolved by fluorescence proximity sensing
Communications Biology (2022)
-
Complex regulation of Gephyrin splicing is a determinant of inhibitory postsynaptic diversity
Nature Communications (2022)
-
Recruitment of Plasma Membrane GABA-A Receptors by Submembranous Gephyrin/Collybistin Clusters
Cellular and Molecular Neurobiology (2022)
-
Profiling Analysis of Circular RNA and mRNA in Human Temporal Lobe Epilepsy with Hippocampal Sclerosis ILAE Type 1
Cellular and Molecular Neurobiology (2022)