Proteins

  • Article
    | Open Access

    Dynamin mediates the fission of vesicles during endocytosis. Here, the authors report the cryoEM structure of a super-constricted two-start dynamin 1 filament- one of the two known helical forms of dynamin, with insights into the molecular mechanisms of dynamin-mediated membrane scission.

    • Jiwei Liu
    • , Frances Joan D. Alvarez
    •  & Peijun Zhang
  • Article
    | Open Access

    The assembly of branched actin networks depends on the heterodimeric capping protein CP/CapZ. Combining cryoEM, in vitro reconstitution and cell biological assays, the authors show that CP not only prevents actin filament elongation but also selectively masks actin filament ends to promote nucleation.

    • Johanna Funk
    • , Felipe Merino
    •  & Peter Bieling
  • Article
    | Open Access

    The lipid composition of the plasma membrane defines the localisation of KRAS and its oncogenic function. Here the authors show that EFR3A binds to active KRAS to recruit PI4KA and alters the lipid composition of the plasma membrane to promote KRAS oncogenic signalling and tumorigenesis.

    • Hema Adhikari
    • , Walaa E. Kattan
    •  & Christopher M. Counter
  • Article
    | Open Access

    Cytosolic amino acid concentrations are carefully maintained, but how homeostasis occurs is unclear. Here, the authors show that amino acid transporters primarily determine intracellular amino acid levels and develop a model that predicts a perturbation response similar to experimental data.

    • Gregory Gauthier-Coles
    • , Jade Vennitti
    •  & Stefan Bröer
  • Article
    | Open Access

    CD47 is a transmembrane receptor involved in the regulation of various signalling pathways and a promising target for immuno-oncology therapeutics. Here, the authors present the crystal structure of full-length human CD47 and provide insights into the molecular mechanism of CD47-mediated signalling.

    • Gustavo Fenalti
    • , Nicolas Villanueva
    •  & Kandasamy Hariharan
  • Article
    | Open Access

    Misfolded proteins are ubquitinated and subsequently condensed by cargo receptors for selective autophagy. Here, the authors use in vitro reconstitution to elegantly dissect how the receptors p62/SQSTM1, NBR1 and TAX1BP1 contribute to p62-ubiquitin condensate formation and degradation by autophagy.

    • Eleonora Turco
    • , Adriana Savova
    •  & Sascha Martens
  • Article
    | Open Access

    Here, the authors engineer microbial production of muscle titin fibers with highly desirable mechanical properties and provide structural analyses that explain the molecular mechanisms underlying high performance of this polymer with potential uses in biomedicine and textile industries, among others.

    • Christopher H. Bowen
    • , Cameron J. Sargent
    •  & Fuzhong Zhang
  • Article
    | Open Access

    Existing methods for multimeric protein complex quantification in single cells suffer from limited selectivity and sensitivity. Here the authors report Single-cell protein Interaction Fractionation Through Electrophoresis and immunoassay Readout (SIFTER) and use this to probe the effects of cellular stress.

    • Julea Vlassakis
    • , Louise L. Hansen
    •  & Amy E. Herr
  • Article
    | Open Access

    The human Tweety homologue (TTYH) family of transmembrane proteins have been suggested to act as chloride channels. Here the authors present cryo-EM structures of the 3 human TTYH paralogs that do not display the expected features of an anion channel, and instead appear to interact with lipid-like compounds residing in the membrane; suggesting an involvement in lipid-associated processes.

    • Anastasiia Sukalskaia
    • , Monique S. Straub
    •  & Raimund Dutzler
  • Article
    | Open Access

    Various strategies to assemble protein building blocks into one-, two- and three-dimensional hierarchical nanostructures were described, but controlling the transformation between those different assemblies is largely uninvestigated. Here, the authors describe a protein interface redesign strategy and use it for the self-assembly transformation of dimeric building blocks from hollow protein nanocage to filament, nanorod and nanoribbon.

    • Xiaorong Zhang
    • , Yu Liu
    •  & Guanghua Zhao
  • Article
    | Open Access

    The nature of the mitochondrial permeability transition pore (PTP) is still under debate. Here, through genetically modified F-ATP synthase, the authors show that PTP formation can be mediated by F-ATP synthase or by adenine nucleotide translocator, suggesting the existence of distinct but related permeability pathways.

    • Andrea Carrer
    • , Ludovica Tommasin
    •  & Paolo Bernardi
  • Article
    | Open Access

    Lipins need to bind cell membranes before they can function as phosphatidic acid phosphatases. Here, the authors elucidate the structural basis of lipin membrane-association and identify a lipin domain with a novel protein fold that is critical for membrane binding and full functionality of lipins.

    • Weijing Gu
    • , Shujuan Gao
    •  & Michael V. Airola
  • Article
    | Open Access

    Mutations in the LaminA gene are the second most common inherited cause of Dilated Cardiomyopathy, a major form of heart failure. Here the authors show that disruption of the nuclear protein SUN1 in cardiomyocytes, by AAV mediated transduction of a SUN1 inhibitor, significantly suppress cardiomyopathy progression, providing a potential therapeutic route to treat this disease.

    • Ruth Jinfen Chai
    • , Hendrikje Werner
    •  & Colin L. Stewart
  • Article
    | Open Access

    Bacteria can secrete diffusible protein toxins that kill competing bacteria. Here, the authors use biochemical, biophysical and structural analyses to show how one of these toxins exploits TolC (a major antibiotic efflux channel) to transport itself across the outer membrane of target cells.

    • Nicholas G. Housden
    • , Melissa N. Webby
    •  & Colin Kleanthous
  • Article
    | Open Access

    Hedgehog signaling is essential for bone formation. Here, the authors show that the transmembrane protein SLITRK5 is a negative regulator of hedgehog signaling in osteoblasts, suggesting it may be a potential therapeutic target to enhance bone formation.

    • Jun Sun
    • , Dong Yeon Shin
    •  & Matthew B. Greenblatt
  • Article
    | Open Access

    The histone acetyltransferase p300 mostly localizes to active chromatin; however, some repressed genes marked with H3K27me3 are also bound by p300. Here the authors show p300 is capable of phase separation, which relies on its catalytic core, and that p300 catalytic activity is decreased in phase-separated droplets that co-localize with H3K27me3-marked chromatin.

    • Yi Zhang
    • , Kyle Brown
    •  & Tatiana G. Kutateladze
  • Article
    | Open Access

    Mitochondrial transport toward both the plus- and minus-ends of microtubules is mediated by motor proteins linked to mitochondria by TRAK adaptor proteins. Here the authors investigate the role of TRAK2 as a bidirectional motor adaptor, and propose a model where TRAK2 coordinates the activities of opposing kinesin-1 and cytoplasmic dynein motors as a single interdependent motor complex.

    • Adam R. Fenton
    • , Thomas A. Jongens
    •  & Erika L. F. Holzbaur
  • Article
    | Open Access

    Nutrient status in the cell regulates autophagy via mTORC1 activity. Here, the authors show that the ubiquitous G protein subunit Gαq contributes to nutrient sensing by promoting formation of an mTOR-p62-Raptor complex in replete conditions, modulating autophagy.

    • Sofía Cabezudo
    • , Maria Sanz-Flores
    •  & Catalina Ribas
  • Article
    | Open Access

    Pannexin 1 (PANX1) is a membrane channel mediating release of signaling molecules to the extracellular space. PANX1 can be activated by GPCRs. Here, the authors elucidate a non-canonical channel activation pathway by α1-adrenergic receptor that involves HDAC6- mediated lysine deacetylation of PANX1.

    • Yu-Hsin Chiu
    • , Christopher B. Medina
    •  & Douglas A. Bayliss
  • Article
    | Open Access

    Calcium signals initiated by IP3 receptors in ER membranes regulate most cellular activities. Here, the authors show that KRas-induced actininteracting protein (KRAP) tethers a small subset of IP3 receptors to actin and licenses them to evoke cytosolic calcium signals.

    • Nagendra Babu Thillaiappan
    • , Holly A. Smith
    •  & Colin W. Taylor
  • Article
    | Open Access

    HAP2 is essential for gamete fusion during fertilization and is conserved among eukaryotes. Here the authors show that species-specific adhesion between Chlamydomonas plus and minus gametes initiates HAP2 to undergo a fusogenic conformational change into homotrimers via a molecular mechanism akin to that of enveloped viruses.

    • Jun Zhang
    • , Jennifer F. Pinello
    •  & William J. Snell
  • Article
    | Open Access

    Pleckstrin homology (PH) domains are presumed to bind phosphoinositides (PIPs) but only few specific interactions are known. Using TIRF microscopy based assays, functional studies and an experimentally validated prediction algorithm, the authors show that specific PIP binding is widespread among human PH domains.

    • Nilmani Singh
    • , Adriana Reyes-Ordoñez
    •  & Jie Chen
  • Article
    | Open Access

    An increase in glycine decarboxylase (GLDC) activity, a key enzyme for glycine catabolism, has been associated to tumourigenesis. Here, the authors show that mTORC1 activation induces GLDC deacetylation which impairs its ubiquitin-associated degradation leading to increased GLDC activity and tumourigenesis.

    • Rui Liu
    • , Lin-Wen Zeng
    •  & Shu Li
  • Article
    | Open Access

    The cryo-EM structure of pentameric green-light absorbing proteorhodopsin together with molecular dynamics simulations and functional studies provides insights into the proton translocation pathway and oligomerization, and a protonation-dependent mechanism for intracellular half channel hydration.

    • Stephan Hirschi
    • , David Kalbermatter
    •  & Dimitrios Fotiadis
  • Article
    | Open Access

    Chromosomal translocations involving the AF10 gene, especially with CALM, are associated with aggressive leukemias. Here the authors show that the PZP domain of AF10, a histone reader, is always excluded/impaired in AF10 fusions, whereas incorporation of this domain downregulates Hoxa genes and blocks leukemogenesis.

    • Brianna J. Klein
    • , Anagha Deshpande
    •  & Tatiana G. Kutateladze
  • Article
    | Open Access

    Mucins play critical roles in maintaining the human microbiome, with their O-glycosylated tandem repeats (TRs) providing important cues for microbiota. Here, the authors develop a cellular platform for producing TRs with defined O-glycan structures to dissect the functions of TR O-glycosylation.

    • Rebecca Nason
    • , Christian Büll
    •  & Yoshiki Narimatsu
  • Article
    | Open Access

    CNNM/CorB proteins are a conserved family of membrane proteins associated with Mg2+ transport. Here, structures of an archaeal CorB protein in apo state and with Mg2+-ATP bound and accompanying biophysical experiments suggest direct Mg2+ transport by CorB proteins.

    • Yu Seby Chen
    • , Guennadi Kozlov
    •  & Kalle Gehring
  • Article
    | Open Access

    Type-III secretion systems (T3SSs) are capable of translocating proteins with high speed while maintaining the membrane barrier for small molecules. Here, a structure-function analysis of the T3SS pore complex elucidates the precise mechanisms enabling the gating and the conformational changes required for protein substrate secretion.

    • Svenja Hüsing
    • , Manuel Halte
    •  & Thibaud T. Renault
  • Article
    | Open Access

    In human cells, P5B‐ATPases execute export of spermine from lysosomes to the cytosol, but the mechanisms of spermine recognition, uptake and transport remain elusive. Here the authors present cryo‐EM structures of a yeast homolog of human ATP13A2‐5, Ypk9, which depict three separate transport cycle intermediates, including spermine‐bound conformations

    • Ping Li
    • , Kaituo Wang
    •  & Pontus Gourdon
  • Article
    | Open Access

    Past studies on protein nucleation have focused on the routes that molecules follow towards a crystalline cluster, while possible interactions that may occur between nuclei have not been investigated. Here, the authors show that in the high supersaturation limit such interactions dominate the nucleation process in the form of inter-nucleus docking driving by oriented attachment.

    • Alexander E. S. Van Driessche
    • , Nani Van Gerven
    •  & Mike Sleutel
  • Article
    | Open Access

    Here, cryo-EM structures of human retinal ABCA4 transporter, either in apo state, in complex with ATP or with the physiological lipid substrate N-retinylidene-phosphatidylethanolamine (NRPE), reveal lateral opening, substrate recognition and suggest ‘lateral access and extrusion’ mechanism for ABCA-mediated lipid transport.

    • Tian Xie
    • , Zike Zhang
    •  & Xin Gong
  • Article
    | Open Access

    The glucagon-like peptide-1 (GLP-1) receptor is a key regulator of glucose homeostasis and a drug target for type 2 diabetes but available GLP-1R agonists are suboptimal due to several side-effects. Here authors report the cryo-EM structure of GLP-1R bound to an ago-allosteric modulator in complex with heterotrimeric Gs which offers insights into the molecular details of ago-allosterism.

    • Zhaotong Cong
    • , Li-Nan Chen
    •  & Ming-Wei Wang
  • Article
    | Open Access

    Mitochondrial ribosomes (mitoribosomes) are characterized by a distinct architecture and thus biogenesis pathway. Here, cryo-EM structures of mitoribosome large subunit assembly intermediates elucidate final steps of 16 S rRNA folding, methylation and peptidyl transferase centre (PTC) completion, as well as functions of several mitoribosome assembly factors.

    • Miriam Cipullo
    • , Genís Valentín Gesé
    •  & Joanna Rorbach
  • Article
    | Open Access

    Maturation of the ribosomal peptidyl transferase center (PTC) is mediated by universally conserved GTPases. Here, cryo-EM structures of mitochondrial ribosomal large subunit assembly intermediates and of mature ribosomes offer insight into the roles of several assembly factors, including GTPBP6’s role in both ribosome biogenesis and recycling.

    • Hauke S. Hillen
    • , Elena Lavdovskaia
    •  & Ricarda Richter-Dennerlein
  • Article
    | Open Access

    The AAA-ATPase Drg1 is a key factor in eukaryotic ribosome biogenesis that initiates cytoplasmic maturation of the large subunit. Here the authors report the structure of Drg1 in complex with its specific inhibitor diazaborine and provide insight into the mechanism of inhibition and specificity of this class of inhibitors.

    • Michael Prattes
    • , Irina Grishkovskaya
    •  & Helmut Bergler
  • Article
    | Open Access

    Sodium/proton exchanger 1 (NHE1) and its obligate binding partner Calcineurin B-homologous protein 1 (CHP1) regulate intracellular pH and volume homeostasis. Structures of the human NHE1-CHP1 complex offer insight into the regulation of NHE1 pH-sensitivity by CHP1 and into the interactions with NHE1 inhibitors.

    • Yanli Dong
    • , Yiwei Gao
    •  & Yan Zhao
  • Article
    | Open Access

    The human PAXT complex and the MTREC complex in fission yeast are important exosome cofactors, serving in the degradation of specific noncoding RNAs. Here, the authors combine structural, biochemical and in vivo methods to show how Red1 recruits the Mtl1 helicase by an interface not seen before in helicase-adaptor complexes.

    • Nikolay Dobrev
    • , Yasar Luqman Ahmed
    •  & Irmgard Sinning
  • Article
    | Open Access

    The activity of translation initiation factor eIF2B is known to be modulated through stress-responsive phosphorylation of its substrate eIF2. Here, the authors uncover the regulation of eIF2B by the binding of sugar phosphates, suggesting a link between nutrient status and the rate of protein synthesis.

    • Qi Hao
    • , Jin-Mi Heo
    •  & Carmela Sidrauski
  • Article
    | Open Access

    Vibrational energy transfer (VET) is essential for protein function as it is responsible for efficient energy dissipation in reaction sites and is linked to pathways of allosteric communication. Here authors equipped a tryptophan zipper with a VET injector and a VET sensor for femtosecond pump probe experiments to map the VET.

    • Erhan Deniz
    • , Luis Valiño-Borau
    •  & Jens Bredenbeck