Anti Ubiquitin-Conjugating Enzyme E2 J1 (Ube2j1)

Western blot using Rockland's affinity purified anti-Ube2j1 antibody shows detection of Ube2j1 in 293 cells over-expressing Myc-Ube2j1 (Lane 2). Lane 1 contains lysate from mock-transfected 293 cells. Personal Communication, A. Weissman & T. Shang, CCR-NCI, Frederick, MD

Most modifiers mature by proteolytic processing from inactive precursors (''a'' = amino acid). Arrowheads point to the cleavage sites. Ubiquitin is expressed either as polyubiquitin or as a fusion with ribosomal proteins. Conjugation requires activating (E1) and conjugating (E2) enzymes that form thioesters (S) with the modifiers. Modification of cullins by RUB involves SCF(SKP1/cullin-1/F-box protein)/CBC(cullin-2/elonginB/elonginC)-like E3 enzymes that are also involved in ubiquitination. In contrast to ubiquitin, the UBLs do not seem to form multi-UBL chains. UCRP(ISG15) resembles two ubiquitin moieties linked head-to-tail. Whether HUB1 functions as a modifier is currently unclear. APG12 and URM1 are distinct from the other modifiers because they are unrelated in sequence to ubiquitin. (From Jentsch & Pyrowolakis (2000); see references below.)