Title

Characterization Of Mammalian Ecm29, A 26 S Proteasome-Associated Protein That Localizes To The Nucleus And Membrane Vesicles

Abstract

In addition to its thirty or so core subunits, a number of accessory proteins associate with the 26 S proteasome presumably to assist in substrate degradation or to localize the enzyme within cells. Among these proteins is ecm29p, a 200-kBa yeast protein that contains numerous HEAT repeats as well as a putative VHS domain. Higher eukaryotes possess a well conserved homolog of yeast ecm29p, and we produced antibodies to three peptides in the human Ecm29 sequence. The antibodies show that Ecm29 is present exclusively on 26 S proteasomes in HeLa cells and that Ecm29 levels vary markedly among mouse organs. Confocal immunofluorescence microscopy localizes Ecm29 to the centrosome and a subset of secretory compartments including endosomes, the ER and the ERGIC. Ecm29 is up-regulated 2-3-fold in toxin-resistant mutant CHO cells exhibiting increased rates of ER-associated degradation. Based on these results we propose that Ecm29 serves to couple the 26 S proteasome to secretory compartments engaged in quality control and to other sites of enhanced proteolysis.

Publication Date

12-24-2004

Publication Title

Journal of Biological Chemistry

Volume

279

Issue

52

Number of Pages

54849-54861

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1074/jbc.M410444200

Socpus ID

11144225834 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/11144225834

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