title: Affinity labeling of the proteasome by a belactosin A derived inhibitor.
abstract: Belactosin A is a potent proteasome inhibitor isolated from Streptomyces metabolites. Here we show that a hydrophobic belactosin A derivative, dansyl-KF33955, can covalently, and specifically, affinity label the catalytic subunits of the 26S proteasome, which consists of the 20S protein degrading core particle and the 19S regulatory particles. The labeling of catalytic subunits proceeds faster in intact proteasomes in vivo than in isolated 20S core particles. These data suggest that the 19S regulatory particle may facilitate entry of the inhibitor into the 20S core particle. This cell-permeable chemical probe is an excellent tool with which to study the interactions of this proteasome inhibitor with proteasomes in intact cells.
authors.affiliation: Graduate School of Bioscience, Nagahama Institute of Bio-Science and Technology, Tamura-cho 1266, Nagahama, Shiga 526-0829, Japan. m_hasegawa@nagahama-i-bio.ac.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kinoshita
authors.forename: Chika
authors.initials: C
authors.lastname: Nishimura
authors.forename: Umechiyo
authors.initials: U
authors.lastname: Matsumura
authors.forename: Masafumi
authors.initials: M
authors.lastname: Shionyu
authors.forename: Masashi
authors.initials: M
authors.lastname: Shionyu
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Ikeda
authors.forename: Tamio
authors.initials: T
authors.lastname: Mizukami
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D020134:Catalytic Domain; D004151:Dipeptides / Q000737:chemistry / Q000494:pharmacology; D015195:Drug Design; D004912:Erythrocytes / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D036341:Intercellular Signaling Peptides and Proteins; D007783:Lactones / Q000737:chemistry / Q000494:pharmacology; D008956:Models, Chemical; D009369:Neoplasms / Q000188:drug therapy; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D000970:Antineoplastic Agents; D004151:Dipeptides; D036341:Intercellular Signaling Peptides and Proteins; C481349:KF33955; D007783:Lactones; D010455:Peptides; C406052:belactosin A; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease