Seminars and Events

Past Events

Category Seminar
Date and Time 2017-09-08 14:00 - 15:00
Venue Seminar Room A7F
Speaker Wei Yung Ding
Affiliation Mechanobiology Institute, National University of Singapore
Title The actin-bundling protein plastin increases cortical connectivity to promote robust polarization and timely cytokinesis in early C. elegans embryogenesi
Poster click here to download(PDF)
Host Li Kun Phng
Abstract Maintenance of the animal cell shape by the actomyosin cortex underlying the plasma membrane and generation of the contractile force within the cortex by non-muscle myosin II drive cellular morphogenetic processes such as gastrulation and cell division. Nevertheless, the regulation of the architecture and dynamics of the cortex by actin-bundling proteins is still poorly understood. Here we demonstrate that the evolutionarily conserved actin-bundling protein plastin (a.k.a fimbrin) is instrumental for the generation of potent cortical actomyosin contractility in the C. elegans zygote. Endogenous plastin, labelled by GFP via CRISPR/Cas9 knock-in, was found to be associating with both formin- and arp2/3-mediated subpopulations of F-actin, and enriched in contractile structures. Plastin was required for effective coalescence of nascent NMY-2 filaments into large contractile foci and for long-range coordinated contractility in the cortex. In the absence of plastin, force-dependent cellular processes during early embryogenesis, i.e. polarization and cytokinesis, were both significantly compromised, and 50% of embryos died during development. Based on these results as well as in silico CytoSim simulations, we propose that by increasing the connectivity of the F-actin meshwork, plastin enables the cortex to generate stronger and more coordinated forces to execute cellular morphogenesis.