Cell biology

  • Article |

    How the sensitivity of biological and pharmacological signalling responses is controlled is poorly understood. Here, computational analyses and cellular experiments show that the sensitivity of a simple biochemical reaction to activators and inhibitors is controlled by negative regulation of cellular signalling.

    • Yu Toyoshima
    • , Hiroaki Kakuda
    •  & Shinya Kuroda
  • Article
    | Open Access

    Glutathione's key role as a modulator of reactive oxygen species levels has recently been challenged. Quintana-Cabreraet al. now provide in vivoevidence supporting an antioxidant and neuroprotective function for γ-glutamylcysteine, which replaces glutathione by acting as glutathione peroxidase-1 cofactor.

    • Ruben Quintana-Cabrera
    • , Seila Fernandez-Fernandez
    •  & Juan P. Bolaños
  • Article |

    Imaging and tracking the motion of single molecules on cell plasma membranes requires high spatial resolution in three dimensions. Honget al. develop a plasmonic ruler based on the fluorescence enhancement of carbon nanotubes on a gold plasmonic substrate, allowing the observation of nanotube endocytosis in three dimensions.

    • Guosong Hong
    • , Justin Z. Wu
    •  & Hongjie Dai
  • Article |

    Interpolar microtubules were thought to be indispensable for eukaryotic cell division. Here, Akera and colleagues demonstrate that the second division of meiosis in yeast can occur in the absence of interpolar microtubules, and identify the forespore membrane as a force producing structure in cell division.

    • Takashi Akera
    • , Masamitsu Sato
    •  & Masayuki Yamamoto
  • Article |

    Zonal occludens and claudin form tight junctions near the apical surface of cells and are important in polarized epithelia. In this study, the translational regulatory sequence-specific RNA binding protein CPEB is shown to be required for the correct localization of zona occluden 1 mRNA in mammary epithelial cells.

    • Kentaro Nagaoka
    • , Tsuyoshi Udagawa
    •  & Joel D. Richter
  • Article
    | Open Access

    Detailed analysis of axis development in mouse embryo has been limited. Morriset al. developed an in vitroculture technique that enables the real-time observation of an anterior visceral endoderm formation and show that cell marker asymmetry within the AVE subdomain dictates the direction of the AVE migration.

    • Samantha A. Morris
    • , Seema Grewal
    •  & Magdalena Zernicka-Goetz
  • Article |

    Actin filaments are involved in the modulation of nuclear shape and function, but mechanistic understanding of these processes is lacking. Versaevelet al. show that orientation and deformation of the nucleus are regulated by lateral compressive forces driven by tension in central actomyosin fibres.

    • Marie Versaevel
    • , Thomas Grevesse
    •  & Sylvain Gabriele
  • Article |

    PADI4 is an enzyme that converts arginine residues to citrulline. Here, Tanikawa and colleagues show that, in response to DNA damage, histone H4 and Lamin C are citrullinated in a p53 and PADI4-dependent manner andPadi4-dependent manner and Padi4 null mice are resistant to radiation-induced apoptosis in the thymus.

    • Chizu Tanikawa
    • , Martha Espinosa
    •  & Koichi Matsuda
  • Article
    | Open Access

    Beclin1 is a key regulator of VPS34-related processes, including autophagy. Liet al. solve the crystal structure of Beclin 1 CC domain, an antiparallel dimer that is rendered metastable by a series of a-d' pairings, which determines its ability to form distinct heterodimers either with Atg14L or UVRAG.

    • Xiaohua Li
    • , Liqiang He
    •  & Yanxiang Zhao
  • Article
    | Open Access

    A systematic approach for identifying the genes responsible for the regulation of spindle orientation in mammals has been lacking. Now, Matsumuraet al. perform a kinase-targeting RNAi screen and identify ABL1, which through the direct phosphorylation of NuMa, is a novel regulator of spindle orientation.

    • Shigeru Matsumura
    • , Mayumi Hamasaki
    •  & Fumiko Toyoshima
  • Article |

    Osteoblast maturation is regulated by c-Src and IL-6, but how these signalling pathways are integrated is not known. Here c-Src is shown to induce 1GFBP5 in immature osteoblasts in a STAT3 and IL-6-dependent manner, in mature osteoblasts, which express lower levels of c-Src, this signalling is lost.

    • Barbara Peruzzi
    • , Alfredo Cappariello
    •  & Anna Teti
  • Article
    | Open Access

    Experience-dependent plasticity and functional adaptation are thought to be restricted to the central nervous and immune systems. This study shows that long-lasting experience-dependent plasticity is a key feature of endocrine cell networks, allowing improved tissue function and hormone output following repeat demand.

    • David J. Hodson
    • , Marie Schaeffer
    •  & Patrice Mollard
  • Article
    | Open Access

    G-protein-coupled receptors sense extracellular cues and transmit the signal to distinct trimeric G-proteins. Stefanet al.show that in response to cAMP, a central and conserved component of the Gαs-coupled receptor cascade, the RII subunit of PKA, specifically binds to and participates in Gαi signaling.

    • Eduard Stefan
    • , Mohan K. Malleshaiah
    •  & Stephen W. Michnick
  • Article |

    The modification of proteins with O-linked-N-acetylglucosamine causes regulation of multiple cellular processes. In this study, Sakaidani and colleagues identify an endoplasmic reticulum O-linked-N-acetylglucosamine transferase in Drosophilathat regulates the adhesion of epithelial cells to the extracellular matrix.

    • Yuta Sakaidani
    • , Tomoko Nomura
    •  & Tetsuya Okajima
  • Article |

    Herpesvirus glycoprotein D binds to nectin 1 and the herpes virus entry mediator protein on the surface of host cells. In this study, Zhanget al. report the crystal structure of glycoprotein D in complex with the immunoglobulin-like domains of nectin 1, which suggests that binding of glycoprotein D to nectin 1 prevents nectin 1 dimerization.

    • Na Zhang
    • , Jinghua Yan
    •  & George F Gao
  • Article
    | Open Access

    Most excitatory synapses in the brain are found on dendritic spines, but the mechanisms underlying synapse formation are poorly understood. Niesmannet al. investigate the role of neurobeachin in synaptogenesis, and find that its deletion leads to fewer spinous synapses and altered postsynaptic currents.

    • Katharina Niesmann
    • , Dorothee Breuer
    •  & Markus Missler
  • Article |

    Cell fusion is involved in many different cellular processes including the fusion of trophoblast cells in the placenta. Matsuuraet al. identify a role for the β-catenin signalling pathway in the regulation of the transcription factor GCM1 and therefore the fusion of syncytiotrophoblast cells.

    • Ken Matsuura
    • , Takafumi Jigami
    •  & Tetsu Akiyama
  • Article |

    Parasites such as malaria elicit an immune response in their host, causing cytokine levels to increase. In this study, a parasite housekeeping gene, tyrosyl-tRNA synthetase, is shown to bind to host macrophages and, once inside the cells, enhance the levels of proinflammatory cytokines.

    • Tarun Kumar Bhatt
    • , Sameena Khan
    •  & Amit Sharma
  • Article |

    The microRNA miR-137 is enriched in the brain of mice and induces the differentiation of adult neural stem cells. Now, Sun and colleagues report that miR-137 negatively regulates proliferation of neurons in embryonic mice and that TLX and LSD1 cooperate to negatively regulate miR-137 expression, blocking premature differentiation.

    • GuoQiang Sun
    • , Peng Ye
    •  & Yanhong Shi
  • Article
    | Open Access

    In the classical model, fast neuronal signalling occurs at specialized presynaptic terminals. Now, Ratnayakaet al. show that stimulus-driven fusion and recycling of synaptic vesicles can occur at axonal sites remote from conventional synapses. These findings have implications for dynamic forms of neuron–neuron communication.

    • Arjuna Ratnayaka
    • , Vincenzo Marra
    •  & Kevin Staras
  • Review Article |

    Hair cells of the inner ear transduce vibrations of the basilar membrane into electrical signals by a process known as mechanotransduction. Recent advances in genetic and molecular tools have led to an improved understanding of mechanotransduction as Peng and colleagues summarize in this Review.

    • Anthony W. Peng
    • , Felipe T. Salles
    •  & Anthony J. Ricci
  • Article |

    Erythropoietin circulates in the blood and is essential for erythropoiesis but its role in metabolic homeostasis has not been examined. Tenget al. show that when the erythropoietin receptor is only expressed in erthyroid cells, mice develop obesity and insulin resistance, suggesting that the receptor has a key role in fat mass accumulation.

    • Ruifeng Teng
    • , Oksana Gavrilova
    •  & Constance Tom Noguchi
  • Article
    | Open Access

    During cell division, a cytoplasmic bridge—the midbody—forms between the nascent daughter cells, but it has been unclear under which conditions this is retained by a daughter cell or released. Now, Ettinger and colleagues show that midbody-release occurs more frequently in stem cells compared with cancer cells.

    • Andreas W. Ettinger
    • , Michaela Wilsch-Bräuninger
    •  & Wieland B. Huttner
  • Article |

    The Golgi membrane is fragmented during mitosis and is subsequently fused following cell division and this process is known to be controlled by ubiquitination. In this study, the ubiquitin ligase HACE1 is shown to be targeted to the Golgi membrane and is required for fusion after the completion of mitosis.

    • Danming Tang
    • , Yi Xiang
    •  & Yanzhuang Wang
  • Article |

    The fusion of satellite cells to muscle fibres during adult life is required for both muscle growth and regeneration but it is unknown whether non-muscle cells contribute to this process. Now, Dellavalle and colleagues show that pericytes, cells associated with the vasculature can contribute to both growth and regeneration of muscle fibres.

    • A. Dellavalle
    • , G. Maroli
    •  & G. Cossu
  • Article |

    The role of phosphatidylinositol(4,5)bisphosphate in exocytosis is unclear. This study shows that inhibition of the p110δ isoform of PI3-kinase promotes a transient increase in phosphatidylinositol(4,5)bisphosphate, leading to a potentiation of exocytosis in chromaffin cells.

    • Peter J. Wen
    • , Shona L. Osborne
    •  & Frédéric A. Meunier
  • Article
    | Open Access

    What controls the binding partner selection of the target of rapamycin protein, TOR, is unknown. Using theCaenorhabditis elegans tail as a model, Nukazuka et al. determine that signals of semaphorin through plexin control the binding partner selection of TOR and are required for the correct organization of rays in the tail.

    • Akira Nukazuka
    • , Shusaku Tamaki
    •  & Shin Takagi
  • Article
    | Open Access

    A bacterial export gate complex transports flagellar proteins across the cytoplasmic membrane, but the mechanism of this process is unclear. Here, the export gate complex is revealed as a proton–protein antiporter that uses separate components of the proton motive force for different steps of the export process.

    • Tohru Minamino
    • , Yusuke V. Morimoto
    •  & Keiichi Namba
  • Article |

    Cellular senescence is characterized by the cessation of cell growth and the expression of the p16 protein. In this study, inhibition or loss of p300, a histone acetyltransferase, is shown to result in senescence that occurs independently of p16 and is associated with histone hypoacetylation and altered replication timing.

    • Alexandre Prieur
    • , Emilie Besnard
    •  & Jean-Marc Lemaitre
  • Article |

    Recent technological advances have allowed the expansion of spermatogonial stem cellsin vitro; however, in vivo conditions are required for the full differentiation of the cells. In this study, an in vitroorgan culture system is developed that allows the differentiation of the germ cells in the laboratory.

    • Takuya Sato
    • , Kumiko Katagiri
    •  & Takehiko Ogawa
  • Article |

    Transforming growth factor-β blocks the activation of pro-inflammatory cytokines, in part by the degradation of Myd88. This study shows that smad ubiquitin regulator proteins are shown to mediate the destruction of Myd8 and are therefore required for the anti-inflammatory effects of transforming growth factor-β.

    • Youn Sook Lee
    • , Jin Seok Park
    •  & Seok Hee Park
  • Article
    | Open Access

    Cell-penetrating peptides can deliver molecular cargoes into living cells, and cross biological membranes by transduction—a non-endocytic mechanism. Here, the transduction efficiency of cyclic arginine-rich peptides is shown to be higher than that of more flexible linear peptides.

    • Gisela Lättig-Tünnemann
    • , Manuel Prinz
    •  & M. Cristina Cardoso
  • Article |

    The development of radial progenitor cells and astroglia in the cerebral cortex depends on the microtubule cytoskeleton. Eomet al. have developed a new mouse model where the microtubules of astrocytes and radial glia cells are fluorescently tagged, facilitating the detailed study of microtubule dynamics and development in these cells.

    • Tae-Yeon Eom
    • , Amelia Stanco
    •  & E.S. Anton
  • Article
    | Open Access

    Pluripotent stem cells can be generated from the somatic cells of humans and are a useful model to study disease. Here, pluripotent stem cells are made from a patient with familial Parkinson's disease, and the resulting neurons exhibit elevated levels of α-synuclein, recapitulating the molecular features of the patient's disease.

    • Michael J. Devine
    • , Mina Ryten
    •  & Tilo Kunath
  • Article
    | Open Access

    Drosophila melanogaster larvae demonstrate chemotaxis towards odours but their navigation mechanism is poorly understood. Using computer-vision tracking, Gomez-Marinet al.show that larvae ascend odour gradients using an active sampling strategy that is analogous to sniffing in vertebrates.

    • Alex Gomez-Marin
    • , Greg J. Stephens
    •  & Matthieu Louis
  • Article |

    Chromatin is rendered silent by epigenetic marks when in proximity to telomeres, and, in yeast, this effect requires the histone-modifying enzyme Sir2. In this study, the human Sir2 family member SIRT6 is shown to modulate the telomere position effect in human cells.

    • Ruth I. Tennen
    • , Dennis J. Bua
    •  & Katrin F. Chua
  • Article |

    How retinoganglion cell axons project correctly to the superior colliculus is poorly understood. Here, projections are shown to require EphB1, EphB2 and ephrin-B1 to terminate in the medial superior colliculus, while ephrin-B2 is essential for the mapping of both dorsal and ventral axons.

    • Sonal Thakar
    • , George Chenaux
    •  & Mark Henkemeyer
  • Article
    | Open Access

    How microtubules are organized correctly in plant cells is not well understood. Ambroseet al. use 4D imaging and computer modelling to show that sharp cell edges induce microtubule depolymerization and that the microtubule-associated protein CLASP mitigates this process to modulate array organization.

    • Chris Ambrose
    • , Jun F. Allard
    •  & Geoffrey O. Wasteneys