ASK1 negatively regulates the 26 S proteasome

J Biol Chem. 2010 Nov 19;285(47):36434-46. doi: 10.1074/jbc.M110.133777. Epub 2010 Sep 15.

Abstract

The 26 S proteasome, composed of the 20 S core and 19 S regulatory particle, plays a central role in ubiquitin-dependent proteolysis. Disruption of this process contributes to the pathogenesis of the various diseases; however, the mechanisms underlying the regulation of 26 S proteasome activity remain elusive. Here, cell culture experiments and in vitro assays demonstrated that apoptosis signal-regulating kinase 1 (ASK1), a member of the MAPK kinase kinase family, negatively regulated 26 S proteasome activity. Immunoprecipitation/Western blot analyses revealed that ASK1 did not interact with 20 S catalytic core but did interact with ATPases making up the 19 S particle, which is responsible for recognizing polyubiquitinated proteins, unfolding them, and translocating them into the 20 S catalytic core in an ATP-dependent process. Importantly, ASK1 phosphorylated Rpt5, an AAA ATPase of the 19 S proteasome, and inhibited its ATPase activity, an effect that may underlie the ability of ASK1 to inhibit 26 S proteasome activity. The current findings point to a novel role for ASK1 in the regulation of 26 S proteasome and offer new strategies for treating human diseases caused by proteasome malfunction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Cells, Cultured
  • Embryo, Mammalian / cytology
  • Embryo, Mammalian / metabolism
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Glioma / genetics
  • Glioma / metabolism
  • HeLa Cells
  • Humans
  • Immunoprecipitation
  • Kidney / cytology
  • Kidney / metabolism
  • MAP Kinase Kinase Kinase 5 / antagonists & inhibitors
  • MAP Kinase Kinase Kinase 5 / genetics
  • MAP Kinase Kinase Kinase 5 / metabolism*
  • Mice
  • Mice, Knockout
  • Neuroblastoma / genetics
  • Neuroblastoma / metabolism
  • Proteasome Endopeptidase Complex / metabolism*
  • Protein Subunits
  • RNA, Messenger / genetics
  • RNA, Small Interfering / genetics
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Ubiquitination

Substances

  • Protein Subunits
  • RNA, Messenger
  • RNA, Small Interfering
  • MAP Kinase Kinase Kinase 5
  • Proteasome Endopeptidase Complex
  • ATP dependent 26S protease