Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Structure. 2008 Sep 10;16(9):1296-304. doi: 10.1016/j.str.2008.07.001.

PACemakers of proteasome core particle assembly.

Author information

  • 1Departamento de Química, Bioquímica e Farmácia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8000-117 Faro, Portugal. pcramos@ualg.pt

Abstract

The 26S proteasome mediates ubiquitin-dependent proteolysis in eukaryotic cells. A number of studies including very recent ones have revealed that assembly of its 20S catalytic core particle is an ordered process that involves several conserved proteasome assembly chaperones (PACs). Two heterodimeric chaperones, PAC1-PAC2 and PAC3-PAC4, promote the assembly of rings composed of seven alpha subunits. Subsequently, beta subunits join to form half-proteasome precursor complexes containing all but one of the 14 subunits. These complexes lack the beta7 subunit but contain UMP1, another assembly chaperone, and in yeast, at least to some degree, the activator protein Blm10. Dimerization of two such complexes is triggered by incorporation of beta7, whose C-terminal extension reaches out into the other half to stabilize the newly formed 20S particle. The process is completed by the maturation of active sites and subsequent degradation of UMP1 and PAC1-PAC2.

PMID:
18786393
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk