ECM29 Homolog (ECM29)

Ecm29p, a 200-kDa yeast protein that contains numerous HEAT repeats as well as a putative VHS domain. 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 toxinresistant mutant CHO cells exhibiting increased rates of ER-associated degradation.Ecm29 serves to couple the 26 S proteasome to secretory compartments engaged in quality control and to other sites of enhanced proteolysis.