Cytoskeleton

  • Article
    | Open Access

    The γ-tubulin ring complex (γTuRC) nucleates microtubules at the centrosome, but how this function is related to γTuRC subcentrosomal distribution is unclear. Here the authors show that γTuRC in the centriole lumen has a nucleation-independent role in centriole integrity and cilium assembly.

    • Nina Schweizer
    • , Laurence Haren
    •  & Jens Lüders
  • Article
    | Open Access

    Biomechanical mechanisms orchestrating stem cell dynamics in development remain unclear. Here the authors show that guidance receptor Plexin-B2 organizes actomyosin contractility, cytoskeletal tension and adhesion during multicellular development of human embryonic stem cells and neuroprogenitor cells.

    • Chrystian Junqueira Alves
    • , Rafael Dariolli
    •  & Roland H. Friedel
  • Article
    | Open Access

    Ciliary beating is mediated by the axonemal central pair microtubules, though how these non-centrosomal microtubules form is poorly understood. Here the authors show that a trio of proteins act cooperatively to initiate central microtubule formation in mammals.

    • Hao Liu
    • , Jianqun Zheng
    •  & Xiumin Yan
  • Article
    | Open Access

    Cell migration is essential for many physiological processes. Its deregulation causes cancer metastasis and it is not well understood how it is tightly controlled. We identify NHSL1 as a negative regulator of actin nucleating Scar/WAVE-Arp2/3 complexes, cell protrusion stability, and cell migration.

    • Ah-Lai Law
    • , Shamsinar Jalal
    •  & Matthias Krause
  • Article
    | Open Access

    Actin-based structures in cells and tissues are built and maintained through a poorly understood balance between assembly and disassembly. Here, our findings provide insights into how factors known to promote these opposing effects dynamically integrate to shape cells and tissue systems.

    • Elena E. Grintsevich
    • , Giasuddin Ahmed
    •  & Jonathan R. Terman
  • Article
    | Open Access

    Cytokinetic ring constriction during cell division requires actin but curiously is independent of myosin in many organisms. Here, the authors show that anillin, a protein enriched in the contractile ring, is a non-motor actin crosslinker that generates contractile force in lieu of a molecular motor.

    • Ondřej Kučera
    • , Valerie Siahaan
    •  & Zdenek Lansky
  • 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

    Septins are cytoskeletal proteins that assemble into complexes and contribute to immunity by entrapping intracellular bacteria in cage-like structures. Here, Lobato-Márquez et al. reconstitute septin cages in vitro using purified recombinant complexes, and study how these recognize bacterial cells and assemble as filaments on their surface.

    • Damián Lobato-Márquez
    • , Jingwei Xu
    •  & Serge Mostowy
  • Article
    | Open Access

    Sarcomeres, the building blocks of striated muscles, comprise ordered actomyosin arrays involved in force production. Here, the authors visualize sarcomere organization in neonatal cardiomyocytes with in situ cryo-electron tomography, revealing a reduced order of the thin filaments, their sliding and functional states enabling contraction.

    • Laura Burbaum
    • , Jonathan Schneider
    •  & Marion Jasnin
  • Article
    | Open Access

    Non-centrosomal microtubules provide essential functions in many cells, but the mechanisms of their formation are poorly understood. Here, the authors show that during tube formation of the Drosophila salivary glands, microtubules are released from a single active centrosome via katanin, triggering recruitment of Patronin, and leading to formation of a non-centrosomal network key to the tube invagination process.

    • Ghislain Gillard
    • , Gemma Girdler
    •  & Katja Röper
  • Article
    | Open Access

    Bacterial pathogens can subvert host cell processes through secreted proteins but the precise mechanisms and repertoire of proteins remains unclear. Here the authors report that a bacterial effector protein of Xanthomonas campestris, XopR, undergoes liquid-liquid phase separation to hijack the host cell actin cytoskeleton.

    • He Sun
    • , Xinlu Zhu
    •  & Yansong Miao
  • Article
    | Open Access

    Centrioles are ancient organelles with a conserved architecture and their rigidity is thought to restrict microtubule sliding. Here authors show that, in mammalian sperm, the atypical distal centriole and its surrounding atypical pericentriolar matrix form a dynamic basal complex that facilitates a cascade of internal sliding deformations, coupling tail beating with asymmetric head kinking.

    • Sushil Khanal
    • , Miguel Ricardo Leung
    •  & Tomer Avidor-Reiss
  • Article
    | Open Access

    KIF14 is a mitotic kinesin whose malfunction is associated with cerebral and renal developmental defects and several cancers. Here the authors use cryoEM to determine 20 structures of KIF14 constructs bound to microtubules in the presence of different nucleotide analogues and provide the structural basis for a coordinated chemo-mechanical kinesin translocation model.

    • Matthieu P.M.H. Benoit
    • , Ana B. Asenjo
    •  & Hernando Sosa
  • Article
    | Open Access

    It is difficult to apply SMLM to complex biological tissues. Here the authors report REALM, Robust and Effective Adaptive Optics in Localisation Microscopy, to improve SMLM in tissue and use this to resolve the organisation of spectrin in the axon initial segment in brain tissue.

    • Marijn E. Siemons
    • , Naomi A. K. Hanemaaijer
    •  & Lukas C. Kapitein
  • Article
    | Open Access

    How the developing skin epidermis is transformed from a simple single-layered epithelium to a complex and stratified barrier is still an open question. Here, the authors provide a model based on high proliferation and delamination of the keratinocyte progenitors that support the stratification process.

    • Mareike Damen
    • , Lisa Wirtz
    •  & Hisham Bazzi
  • Article
    | Open Access

    Cortical microtubules (MTs) in Apicomplexa are specialized MTs involved in maintaining the parasite’s shape and are, as such, unusually stable. Here, cryo-EM analysis of cortical MTs from Toxoplasma gondii offers insight into the mechanism of their stabilization by three bona fide microtubule inner proteins.

    • Xiangli Wang
    • , Yong Fu
    •  & Rui Zhang
  • Article
    | Open Access

    During cell division, the actin cytoskeletal network at both the equatorial contractile ring and cell cortex are known to play a role, but the regulation of γ-actin during cytokinesis is less well understood. Here, the authors show that recruitment of β-actin to the contractile ring and loss of γ-actin from the cell poles is required for completion of cell division.

    • Anan Chen
    • , Luisa Ulloa Severino
    •  & Andrew Wilde
  • Article
    | Open Access

    Cytoskeletal networks support and direct cell shape and guide intercellular transport, but relatively little is understood about the self-organization of cytoskeletal components on the scale of an entire cell. Here, authors use an in vitro system and observe the assembly of different types of actin networks and the condensation of membrane-bound actin into single rings.

    • Thomas Litschel
    • , Charlotte F. Kelley
    •  & Petra Schwille
  • Article
    | Open Access

    Sensory perception and metabolic homeostasis are known to deteriorate with ageing, while mechanisms underlying their deterioration remain poorly understood. Here, the authors demonstrate that decrease of intraflagellar transport in the cilia of sensory neurons impairs sensory perception and metabolism in ageing C. elegans.

    • Yincong Zhang
    • , Xiaona Zhang
    •  & Yidong Shen
  • Article
    | Open Access

    New contractile units are required during cardiac hypertrophy, though it remains unclear precisely where and how these new sarcomeres are added. Here the authors reveal that in the heart, microtubules spatiotemporally regulate mRNAs and ribosomes to build new sarcomeres, a role which is essential for growth.

    • Emily A. Scarborough
    • , Keita Uchida
    •  & Benjamin L. Prosser
  • Article
    | Open Access

    Monitoring the activity of the processive motor protein kinesin-1 in live cells is currently difficult. Here the authors report the fluorogenic small molecule QPD-OTf, a kinesin-1 substrate that causes activity-dependent dye precipitation.

    • Simona Angerani
    • , Eric Lindberg
    •  & Nicolas Winssinger
  • Article
    | Open Access

    Uncoupling of mature oocytes from somatic granulosa cells is required for their fertilization. Here the authors show that activation of EGFR signalling in granulosa cells during ovulation triggers ERK-dependent loss of filopodia oocyte adhesion, and Arp2/3 mediated retraction of granulosa cell filopodia.

    • Laleh Abbassi
    • , Stephany El-Hayek
    •  & Hugh J. Clarke
  • Article
    | Open Access

    TRPV4 dominant mutations cause neuropathy. Here, the authors show that TRPV4 binds and interacts with RhoA, modulating the actin cytoskeleton. Neuropathy-causing mutations of TRPV4 disrupt this complex, leading to RhoA activation and impairment of neurite extension in cultured cells and flies.

    • Brett A. McCray
    • , Erika Diehl
    •  & Charlotte J. Sumner
  • Article
    | Open Access

    The pathogen Campylobacter jejuni invades intestinal cells after secreting protein effectors into the host cell cytosol via the flagellum. Here, Negretti et al. show that one of these effectors, CiaD, binds to host protein IQGAP1, thus leading to unconstrained activity of small GTPase Rac1, which modulates actin reorganization and bacterial internalization.

    • Nicholas M. Negretti
    • , Christopher R. Gourley
    •  & Michael E. Konkel
  • Article
    | Open Access

    Multicilia are complex, and how they achieve accurate assembly is unclear. Here, the authors show that fibrogranular materials condense into spherical cores and function in multicilia formation by tightly associating with deuterosomes and concentrating specific proteins to promote proper assembly.

    • Huijie Zhao
    • , Qingxia Chen
    •  & Xueliang Zhu
  • Article
    | Open Access

    Kinesin motor proteins are critical for maintaining mitotic spindle integrity, which is important for chromosome stability. Here, the authors show that the kinesin motor protein, KIF18A, permits the proliferation of chromosomally unstable cells and knockdown of KIF18A induces centrosome fragmentation.

    • Carolyn Marquis
    • , Cindy L. Fonseca
    •  & Jason Stumpff
  • Article
    | Open Access

    Mutations that cause tissue mosaicism have been identified in individuals with severe congenital defects. Here, the authors show that mosaic deletion of Vangl2 in the murine neuroepithlium causes spina bifida by preventing apical constriction via reduced myosin II and tubulin organisation.

    • Gabriel L. Galea
    • , Eirini Maniou
    •  & Andrew J. Copp
  • Article
    | Open Access

    In a newly fertilized egg, maternal and paternal chromosomes are enclosed in two separate pronuclei but the mechanisms in mammals for pronuclear movement are unclear. Here, the authors report that both F-actin and microtubule polymerization act in concern to drive inward movement of pronuclei towards the cell centre.

    • Kathleen Scheffler
    • , Julia Uraji
    •  & Melina Schuh
  • Article
    | Open Access

    Contact stimulation of migration drives tissue morphogenesis. Here the authors report that filopodia-based contact-dependent asymmetry of cell–matrix adhesion drives directional movement, whereas contractile actin cables contribute to the integrity of the migrating cell cluster in the myotubes of Drosophila developing testes.

    • Maik C. Bischoff
    • , Sebastian Lieb
    •  & Sven Bogdan
  • Article
    | Open Access

    Myosin-7a is found in actin bundles, microvilli and stereocilia, and plays conserved roles in hearing and vision. Here the authors identify M7BP, a myosin-7a binding protein that activates and dimerizes myosin-7a, enabling cargo transport and assembly of actin bundles and filopodia-like protrusions

    • Rong Liu
    • , Neil Billington
    •  & James R. Sellers
  • Article
    | Open Access

    Actin polymerization provides force for vital processes of the eukaryotic cell, but our understanding of actin dynamics and energetics remains limited due to the lack of high-quality probes. Here authors identify a family of highly sensitive fluorescent nucleotide analogues which bind to actin and provide energy to power actin-based processes.

    • Jessica Colombo
    • , Adrien Antkowiak
    •  & Alphée Michelot
  • Article
    | Open Access

    Axonemal dyneins are tethered to doublet microtubules inside cilia to drive ciliary beating but the mechanisms regulating their localization and function are poorly understood. Here authors report a cryo-EM reconstruction of a three-headed axonemal dynein natively bound to doublet microtubules isolated from cilia which provides a framework to understand the roles of individual subunits.

    • Travis Walton
    • , Hao Wu
    •  & Alan Brown
  • Article
    | Open Access

    The cytoplasm in mammalian cells is considered homogeneous. Here authors report that the cytoplasmic fluidity is regulated in the blebbing cells, which is regulated by calcium concentration in the expanding blebs and involves the STIM-Orai1 pathway.

    • Kana Aoki
    • , Shota Harada
    •  & Junichi Ikenouchi
  • Article
    | Open Access

    Mitochondrial trafficking is carefully regulated and functionally important in neurons. Here, the authors screen C. elegans for abnormal mitochondrial distribution and identify metaxin-1 and -2, which bind Miro and microtubule motor proteins to promote mitochondrial trafficking.

    • Yinsuo Zhao
    • , Eli Song
    •  & Kang Shen
  • Article
    | Open Access

    Enterohemorrhagic Escherichia coli (EHEC) induces formation of attaching and effacing lesions in the intestine. Here, Huang et al. use human intestinal cells and a C. elegans model of infection to show that the process is mediated by a host signaling pathway involving cyclin-dependent kinase CDK1 and formin CYK1.

    • Cheng-Rung Huang
    • , Cheng-Ju Kuo
    •  & Chang-Shi Chen
  • Article
    | Open Access

    The actin-related protein (Arp)2/3 complex nucleates branched actin filament networks pivotal for cell migration, endocytosis and pathogen infection. Here, authors report a 9.0 Å resolution structure of the actin filament Arp2/3 complex branch junction in cells using cryo-electron tomography and subtomogram averaging.

    • Florian Fäßler
    • , Georgi Dimchev
    •  & Florian K. M. Schur
  • Article
    | Open Access

    Muscle cells express an adhesion molecule called metavinculin, which has been associated with cardiomyopathies. Here, the authors employed molecular tension sensors to reveal that metavinculin expression modulates cell adhesion mechanics and they develop a mouse model to demonstrate that the presence of metavinculin is not as critical for heart muscle function as previously thought.

    • Verena Kanoldt
    • , Carleen Kluger
    •  & Carsten Grashoff
  • Article
    | Open Access

    The assembly of actin filaments into distinct cytoskeletal structures plays a critical role in cell physiology. Here, the authors use a combination of live cell imaging and in vitro single molecule binding measurements to show that tandem calponin homology domains (CH1–CH2) are sensitive to actin filament conformation, biasing their subcellular localization.

    • Andrew R. Harris
    • , Pamela Jreij
    •  & Daniel A. Fletcher
  • Article
    | Open Access

    Breakdown of vascular barriers is a major complication of inflammatory diseases. However, the mechanisms underlying platelet recruitment to inflammatory micro-environments remains unclear. Here, the authors identify haptotaxis as a key effector function of immune-responsive platelets

    • Leo Nicolai
    • , Karin Schiefelbein
    •  & Florian Gaertner