Elucidating the biological role and regulation of conserved actin cytoskeleton proteins in the budding yeast Saccharomyces cerevisiae
By: by Christine L. Humphries.
Published: 2004
Language: eng
Number of pages: 238
Description: The function of the actin cytoskeleton in the budding yeast,  Saccharomyces cerevisiae depends on the ability of a network of actin filaments and other proteins to change dynamically in response to intra and extra-cellular cues. Actin-binding proteins and regulatory proteins interact and function together to regulate the assembly and disassembly of the actin filaments. The specific activity and biological function of many of these actin-associated proteins remains unclear. In this doctoral work, I have sought to uncover the biological role and regulation of several conserved actin cytoskeleton proteins: coronin (Crn1), the Arp2/3 complex and the yeast amphiphysins (Rvs161 and Rvs167). I report on a novel mode of Arp2/3 complex regulation mediated by the highly conserved actin binding protein coronin. I show that yeast coronin (Crn1) physically associates with the Arp2/3 complex and inhibits WA- and Abp1-activated actin nucleation in vitro. I also report on a possible role for phosphorylation in regulating the activity of Crn1  in vivo. I show evidence that Crn1 is a substrate for Pcl-Pho85  in vitro and that Pho85 regulates the interaction between Cm1 and the Arp2/3 complex in vivo. I also present genetic and biochemical evidence that the yeast amphiphysin proteins, Rvs161 and Rvs167, function together during vegetative growth and during mating. In addition, I have identified an essential role for the SH3 domain of Rvs167 in the absence of the actin cytoskeleton proteins Sla1 and End3. My work identifies novel roles for Crn1 as a regulator of Arp2/3-dependent actin nucleation, provides evidence that the activity of Crn1 may be regulated by phosphorylation and shows evidence for a role for the Rvs161--167 complex in a variety of cellular processes, including mating.
Notes: Adviser: Brenda Andrews.

Thesis (Ph.D.)--University of Toronto, 2004.

Electronic version licensed for access by U. of T. users.

Source: Dissertation Abstracts International, Volume: 65-10, Section: B, page: 4942.