School of Biomedical Sciences is pleased to invite you to join the following seminar:

Date: 15 November, 2023 (Wednesday)
Time: 5:00 pm – 6:00 pm
Venue: Lecture Theatre 2, G/F, William M.W. Mong Block, 21 Sassoon Road

Speaker: Professor Randy Schekman, Department of Molecular and Cell Biology, University of California, Berkeley; Investigator, Howard Hughes Medical Institute; 2013 Nobel Laureate in Physiology or Medicine
Talk Title: Exosomes and tubular connections in membrane repair and intercellular protein and RNA traffic
 

Biography

Professor Randy Schekman is a Professor in the Department of Molecular and Cell Biology, University of California, Berkeley, and an Investigator of the Howard Hughes Medical Institute. He studied the enzymology of DNA replication as a graduate student with Arthur Kornberg at Stanford University. His current interest in cellular membranes developed during a postdoctoral period with S. J. Singer at the UC Diego. Among his awards are the Gairdner International Award, the Albert Lasker Award in Basic Medical Research and the Nobel Prize in Physiology or Medicine, which he shared with James Rothman and Thomas Südhof. He served as the Editor of the Annual Reviews of Cell and Developmental Biology and as Editor-in-Chief of the Proceedings of the NAS and eLife. Beginning in 2018, Schekman has served as the Scientific Director of “Aligning Science Across Parkinson’s Disease” a major philanthropic effort organized along with The Michael J. Fox Foundation to identify molecular and cellular mechanisms in the initiation and progression of Parkinson’s Disease (https://parkinsonsroadmap.org).

Schekman’s laboratory investigates the mechanism of vesicular traffic in the secretory pathway in eukaryotic cells. Currently the lab investigates the mechanism of biogenesis of extracellular vesicles including how small RNAs are sorted for secretion in exosomes and the means by which these vesicles are internalized and function in target cells.

Abstract
Virtually all cells produce extracellular vesicles (EVs).  Mammals export two broad classes:  Shedded vesicles that bud from the plasma membrane and exosomes that are secreted from a reservoir of vesicles that bud into a multivesicular body (MVB).  Much remains to be learned about the regulation of secretion and function of these two categories of vesicles.  We have found that both populations of vesicles are exported because of plasma membrane damage repair.  These repair processes occur under normal physiologic conditions and my account for the abundance of EVs in all bodily fluids.  Some evidence suggests that EVs may be a vehicle for intercellular traffic of proteins and RNA.  We devised test of this by engineering the capture of Cas9 and a gRNA into exosomes produced by a donor cell line and a reporter cell line with a crippled from of N-luciferase whose expression is promoted by the introduction of Cas9 and an appropriate gRNA into the acceptor cell.  Although exosomes enriched in Cas9/gRNA are internalized into acceptor cells, little functional delivery of Cas9 is observed, possibly because of a failure of membrane fusion of exosomes to the inner surface of an endosome.  In contrast, when donor and acceptor cells are co-cultured with physical contact, Cas9/gRNA intercellular transfer is promoted by the formation of open-ended intercellular membrane tubular connections.

ALL ARE WELCOME

Should you have any enquiries, please feel free to contact Miss Angela Wong at 3917 9216.