Novel lipid regulation of vacuolar fusion in saccharomyces cerevisiae
type: CreativeWork
description: Intracellular trafficking is essential for proper maturation and functioning of eukaryotic cells. The terminal stage of trafficking is the membrane fusion of two distinct compartments leading to the mixing of contents. In order to regulate this process organelles are enriched with specific fusion proteins termed SNAREs. While the core fusion machinery is well understood, relatively little is known about the role lipid regulation plays in membrane fusion. It has been well established that enrichment of specific regulatory lipids leads to recruitment and activation of the fusion machinery. Additionally these lipids are modified by specific kinases, phosphatases and lipases allowing regulation of the different stages of fusion. Furthermore, some regulatory lipids have been found to enhance the fission process. Taken together, it becomes evident that the dynamic lipid remodeling of membranes plays a key role in both membrane fusion and fission. In order to study in vitro membrane fusion with a system containing endogenous proteins and lipid, the vacuole from Saccharomyces cerevisiae is utilized. Yeast vacuoles undergo homotypic vacuolar fusion which is utilized to maintain homeostasis and occurs during inheritance. During the fusion pathway, vacuoles accumulate the glycerophospholipid phosphatidylinositol 3-phosphate (PI3P). PI3P is a positive regulatory of fusion that functions through the recruitment of multiple components of the vacuolar fusion machinery including the soluble SNARE Vam7. Vam7 interacts with PI3P through its PX domain and utilizes this interaction for proper localization to the vacuole. In Chapter 2 I show that the interaction of Vam7 with PI3P is allosterically regulated by the Vam7 Mid-domain (MD). I identified a polybasic region in the MD and found that mutating these basic residues to alanine, generating Vam7-6A, led to impaired vacuolar fusion. This was due to decreased association with its cognate SNAREs as well as the HOPS tethering complex. Th…
abstract: Intracellular trafficking is essential for proper maturation and functioning of eukaryotic cells. The terminal stage of trafficking is the membrane fusion of two distinct compartments leading to the mixing of contents. In order to regulate this process organelles are enriched with specific fusion proteins termed SNAREs. While the core fusion machinery is well understood, relatively little is known about the role lipid regulation plays in membrane fusion. It has been well established that enrichment of specific regulatory lipids leads to recruitment and activation of the fusion machinery. Additionally these lipids are modified by specific kinases, phosphatases and lipases allowing regulation of the different stages of fusion. Furthermore, some regulatory lipids have been found to enhance the fission process. Taken together, it becomes evident that the dynamic lipid remodeling of membranes plays a key role in both membrane fusion and fission. In order to study in vitro membrane fusion with a system containing endogenous proteins and lipid, the vacuole from Saccharomyces cerevisiae is utilized. Yeast vacuoles undergo homotypic vacuolar fusion which is utilized to maintain homeostasis and occurs during inheritance. During the fusion pathway, vacuoles accumulate the glycerophospholipid phosphatidylinositol 3-phosphate (PI3P). PI3P is a positive regulatory of fusion that functions through the recruitment of multiple components of the vacuolar fusion machinery including the soluble SNARE Vam7. Vam7 interacts with PI3P through its PX domain and utilizes this interaction for proper localization to the vacuole. In Chapter 2 I show that the interaction of Vam7 with PI3P is allosterically regulated by the Vam7 Mid-domain (MD). I identified a polybasic region in the MD and found that mutating these basic residues to alanine, generating Vam7-6A, led to impaired vacuolar fusion. This was due to decreased association with its cognate SNAREs as well as the HOPS tethering complex. Th…
author: Miner, Gregory E.
language: en
keywords: Vacuole Fusion, Phosphatidylinositol 3-phosphate, Phosphatidylinositol 3,5-bisphosphate, membrane fusion, lipid, SNARE, Membrane fluidity, Calcium transport
date published: 2018-09-04T20:47:01Z
date modified: 2026-07-22T22:24:38Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/101295