Scott David Emr, Ph.D. - "Sorting out membrane traffic to the lysosome: Ubiquitin, ESCRTs and protein quality control Systems”
Mar 02, 2017
from 11:00 AM to 12:15 PM
|Where||Tigem Auditorium "Vesuvius"|
|Contact Name||Andrea Ballabio|
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The Emr lab has focused its efforts on the molecular mechanisms responsible for the biogenesis, maintenance and function of the lysosome. We have used the single-cell yeast Saccharomyces cerevisiae as a genetic model system to discover and isolate the complex machinery that sort and deliver proteins and enzymes to lysosomes. One set of proteins, the ESCRT complexes (ESCRT-0, -I, -II, -III, and the Vps4 ATPase), sort cell surface receptors and membrane proteins into vesicles that invaginate and bud into the lumen of the late endosome (forming multi-vesicular bodies, MVBs). These MVBs then fuse with the lysosome delivering the vesicles containing the membrane proteins into the lumen of the lysosome where they are degraded. Recent biochemical and structural studies in our lab have identified the ESCRT-III complex as a vesicle budding machine. The ESCRTs mediate not only MVB formation but also, other important cellular processes, including the budding enveloped viruses like HIV, cytokinesis, plasma membrane repair, and nuclear envelope reformation. Recently, our lab also uncovered a pathway for the selective sorting and degradation of lysosomal membrane proteins. This selective degradation process requires activation of a novel lysosome-anchored ubiquitin ligase complex. Lysosomal membrane proteins are sorted and degraded in the lumen of the lysosome in an ESCRT-dependent process.