MBI PhD Qualifying Exam
Time: 4pm
Date: Thursday, 17 May 2018
Venue: E3-06-04, NUS
Supervisors: Prof Ronen Zaidel-Bar
Investigating the cellular and tissue level function of the actin capping protein Cap-1 using the C elegans as a model system
by Shinjini RAY, Zaidel-Bar Group
Actin structures are diverse, ranging from the transient cytokinetic ring to the stable yet dynamic actin cortex. Actin binding proteins, by regulating actin filament length, orientation and connectivity, modulate the architecture and dynamics of these diverse networks, which in turn affect their force generation capabilities. Filament length is determined by a balance between polymerization and depolymerization, as well as capping of the growing ends of actin. While actin nucleation and elongation promoting factors and actin depolymerization factors have been studied extensively, relatively little is known about the in vivo role of actin capping protein.
With an aim to elucidate the role of capping protein in a physiological context, we are investigating the localization dynamics and function of C. elegans Cap-1. Using an endogenously fluorescently-tagged Cap-1, we mapped its expression and dynamics in the adult worm and in the embryo. In loss of function experiments, we observed defects in embryogenesis and spermatheca contractility, indicating the importance of Cap-1 activity in these contexts. We plan to look at the subcellular localization of Cap-1 and the effects of its depletion on actin organization with the help of electron microscopy. We aim to gain a further understanding of the function of Cap-1 by achieving spatiotemporally controlled knockdown of Cap-1 in different tissues and stages. We will be carrying out two-color live imaging and genetic functional analysis to study the relationship between Cap-1 and the actin nucleators Arx-2 (Arp2/3) and Cyk-1 (formin) and the adherens junction components Hmp-1 (alpha- catenin), Hmp-2 (beta-catenin) and Hmr-1 (E-cadherin). Our study will provide novel insight about the in vivo role of Cap-1 in regulating actin network architecture and/or dynamics and may uncover novel interactions and physiological functions of Cap-1.
**Please note the examination following the seminar is closed-door**
