In vivo analysis of polarized lipid/GTPase function and dynamics in yeast


Supervising PI

Robert Arkowitz (website)

Project Description

Background

Lipids, such as phosphatidylinositol phosphate, and small GTPases, such as the Rho GTPase Cdc42, have been shown to play critical roles in polarized growth in a range of organisms. However, whether clusters of lipids or activated GTPases can drive polarized growth in response to external stimuli remain unknown. Specifically, can cellular asymmetries be initiated and maintained by generation of such clusters? and by what mechanisms? Understanding the dynamics and functions of localized lipids and activated GTPases will also require mathematical modeling. In this project we will take advantage of light dependent recruitment systems to probe the distribution, dynamics and function of lipids and activated GTPases in polarized growth in response to external stimuli.

Objectives

  • Determine the role of site-specific lipid and GTPase clusters in fungal external signal-mediated polarized growth and force generation.
  • Determine whether artificially generated clusters of lipid and activated GTPases can drive polarized growth and/or compete with endogenous growth sites.

Methodology

High resolution live cell microscopy, fungal molecular genetics, optogenetics and biochemistry.

Collaborators

Key publications

  1. Ghugtyal V, Garcia-Rodas R, Seminara A, Schaub S, Bassilana M, Arkowitz RA. Phosphatidylinositol-4-phosphate-dependent membrane traffic is critical for fungal filamentous growth. Proc Natl Acad Sci U S A. 2015 Jul 14;112(28):8644–9.
  2. Arkowitz RA, Bassilana M. Rho GTPase-phosphatidylinositol phosphate interplay in fungal cell polarity. Biochem Soc Trans. 2014 Feb;42(1):206–11.
  3. Guillas I, Vernay A, Vitagliano J-J, Arkowitz RA. Phosphatidylinositol 4,5-bisphosphate is required for invasive growth in Saccharomyces cerevisiae. J Cell Sci. 2013 Aug 15;126(Pt 16):3602–14.
  4. Vernay A, Schaub S, Guillas I, Bassilana M, Arkowitz RA. A steep phosphoinositide bis-phosphate gradient forms during fungal filamentous growth. J Cell Biol. 2012 Aug 20;198(4):711–30.