Characterizing the role of UBE3C in proteasome processivity

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Abstract/Contents

Abstract
To maintain protein homeostasis, cells must balance protein synthesis with protein degradation. Accumulation of misfolded or partially degraded proteins can lead to the formation of pathological protein aggregates. Here we report the use of destabilizing domains, proteins whose folding state can be reversibly tuned using a high-affinity ligand, as model substrates to interrogate cellular protein quality control mechanisms in mammalian cells using a forward genetic screen. Upon knockdown of UBE3C, an E3 ubiquitin ligase, a reporter protein consisting of a destabilizing domain fused to GFP is degraded more slowly and incompletely by the proteasome. Partial proteolysis is also observed when UBE3C is present but cannot ubiquitinate substrates because its active site has been mutated, it is unable to bind to the proteasome, or the substrate lacks lysine residues. UBE3C knockdown also results in less substrate polyubiquitination. Finally, knockdown renders cells more susceptible to the Hsp90 inhibitor 17-AAG, suggesting that UBE3C protects against the harmful accumulation of protein fragments arising from incompletely degraded proteasome substrates.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2013
Issuance monographic
Language English

Creators/Contributors

Associated with Chu, Bernard Wen-Bao
Associated with Stanford University, Department of Chemical and Systems Biology.
Primary advisor Wandless, Thomas
Thesis advisor Wandless, Thomas
Thesis advisor Ferrell, James Ellsworth
Thesis advisor Meyer, Tobias
Thesis advisor Wysocka, Joanna, Ph. D
Advisor Ferrell, James Ellsworth
Advisor Meyer, Tobias
Advisor Wysocka, Joanna, Ph. D

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Bernard Wen-Bao Chu.
Note Submitted to the Department of Chemical and Systems Biology.
Thesis Ph.D. Stanford University 2013
Location electronic resource

Access conditions

Copyright
© 2013 by Bernard Wen-Bao Chu
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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