Proteomic analysis of affinity-purified extracellular proteasomes reveals exclusively 20S complexes.

ABSTRACT: Proteasome-mediated proteolysis is important for many basic cellular processes. In addition to their functions in the cell, proteasomes have been found in physiological fluids of both healthy and diseased humans including cancer patients. Higher levels of these proteasomes are associated with higher cancer burden and stage. The etiology and functions of these proteasomes, referred to as circulating, plasmatic, or extracellular proteasomes (ex-PSs), are unclear. Here we show that human cancer cell lines, as well as human endometrium-derived mesenchymal stem cells (hMESCs), release proteasome complexes into culture medium (CM). To define ex-PS composition, we have affinity purified them from CM conditioned by human leukemia cell line K562. Using matrix-assisted laser desorption/ionization (M

SUBMITTER: Kulichkova VA 

PROVIDER: S-EPMC5731941 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature