Enhancement of proteasome activity by a small-molecule inhibitor of USP14.
Proteasomes, the primary mediators of ubiquitin-protein conjugate degradation, are regulated through complex and poorly understood mechanisms. Here we show that USP14, a proteasome-associated deubiquitinating enzyme, can inhibit the degradation of ubiquitin-protein conjugates both in vitro and in cells. A catalytically inactive variant of USP14 has reduced inhibitory activity, indicating that inhibition is mediated by trimming of the ubiquitin chain on the substrate. A high-throughput screen identified a selective small-molecule inhibitor of the deubiquitinating activity of human USP14. Treatment of cultured cells with this compound enhanced degradation of several proteasome substrates that have been implicated in neurodegenerative disease. USP14 inhibition accelerated the degradation of oxidized proteins and enhanced resistance to oxidative stress. Enhancement of proteasome activity through inhibition of USP14 may offer a strategy to reduce the levels of aberrant proteins in cells under proteotoxic stress.
Lee
Byung-Hoon
BH
Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
Lee
Min Jae
MJ
Park
Soyeon
S
Oh
Dong-Chan
DC
Elsasser
Suzanne
S
Chen
Ping-Chung
PC
Gartner
Carlos
C
Dimova
Nevena
N
Hanna
John
J
Gygi
Steven P
SP
Wilson
Scott M
SM
King
Randall W
RW
Finley
Daniel
D
D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D006801:Humans; D051379:Mice; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase / Q000037:antagonists & inhibitors*; D054875:Ubiquitination
D011506:Proteins; C509299:USP14 protein, human; D043222:Ubiquitin Thiolesterase; D046988:Proteasome Endopeptidase Complex