Name and position:
Dr. Thomas Kazmirchuk
MITACs Post-Doctoral Fellow, Department of Biology, Carleton University.
Title:
Indirect-ubiquitylation promotes vacuolar nutrient transporter degradation by the Intralumenal Fragment pathway.
Abstract:
The lysosomal vacuole is a key regulator of cellular metabolism, proteostasis, and nutrient recycling. To regulate these aspects of cellular physiology, lysosomes must undergo membrane fusion to deliver cellular biomaterials to the acidic lysosomal lumen. These biomaterials are then digested by resident lumenal hydrolases into their corresponding nutrients (amino acids, lipids, nucleic acids, sugars). Next, these nutrients are mobilized and returned to the cell for reuse through dedicated nutrient transporters, which decorate the lysosomal membrane. While decades of research has been devoted to the study of vacuolar membrane fusion and cargo degradation by lumenal hydrolases, relatively little is understood about nutrient transporters, specifically how their lifetimes are regulated. Currently, three major protein degradation pathways specific to the regulation of nutrient transporter lifetimes exist. These include: the Vacuolar Recycling and Degradation pathway, microautophagy, and the Intralumenal Fragment (ILF) pathway. While all three pathways contribute to lysosomal membrane remodelling through nutrient transporter degradation, the basis of the contribution of each pathway is under intense scientific debate. My seminar will first introduce the recently discovered ILF pathway and discuss its contribution to lysosome membrane remodelling. I will then describe new results pertaining to the basis of selective protein sorting into the ILF pathway.
Bio:
Dr. Kazmirchuk is a current Post-Doctoral Fellow in the Department of Biology at Carleton University. Previously, he had completed both his B.Sc and M.Sc at Carleton University. As an undergraduate researcher he studied the pathogenesis of the human bacterial pathogen Pseudomonas aeruginosa through studying the secretion of secondary metabolites, including phenazines and siderophores. His graduate work centered on the study of the nonstop RNA decay pathway in Saccharomyces cerevisiae as well as the design of small peptide inhibitors against the Zika virus. Dr. Kazmirchuk then went on to obtain his doctorate at Concordia University in Montreal, where he studied vacuolar membrane remodeling and the basis of selective protein sorting into the recently discovered ILF pathway. His Post-Doctoral work will involve the design and testing of small peptide inhibitors against SARS-CoV-2 (COVID-19) variants as well as cellular signaling systems. In addition, he will also study the mechanism of action underlying consequential agricultural fungicides. His research interests include host-pathogen interactions, autophagy, the molecular basis of lysosomal storage disorders, and protein-protein interactions.