title: Identification of a specific inhibitor of nOGA - a caspase-3 cleaved O-GlcNAcase variant during apoptosis.
abstract: O-linked N-acetylglucosamine (O-GlcNAc) modification of serines/threonines on cytoplasmic proteins is a significant signal regulating cellular processes such as cell cycle, cell development, and cell apoptosis. O-GlcNAcase (OGA) is responsible for the removal of O-GlcNAc, and it thus plays a critical role in O-GlcNAc metabolism. Interestingly, OGA can be cleaved by caspase-3 into two fragments during apoptosis, producing an N-terminal fragment (1-413 a.a.), termed nOGA. Here, using 4-MU-GlcNAc (4-methylumbelliferyl 2-acetamido-2-deoxy-β-D-glucopyranoside) as substrate, we found that the nOGA fragment retains high glycosidase activity. To probe the role of nOGA in apoptosis, it is essential to develop a potent and specific nOGA inhibitor. However, many reported inhibitors active at nanomolar concentrations (including PUGNAc, STZ, GlcNAc-statin, and NAG-thiazoline) against full-length OGA were not potent for nOGA. Next, we screened a small triazole-linked carbohydrate library and first identified compound 4 (4-pyridyl-1-(2'-deoxy-2'-acetamido-β-D-glucopyranosyl)-1,2,3-triazole) as a potent and competitive inhibitor for nOGA. This compound shows 15-fold selectivity for nOGA (K(i) = 48 μM) over the full-length OGA (K(i) = 725 μM) and 10-fold selectivity over human lysosomal β-hexosaminidase A&B (Hex A&B) (K(i) = 502 μM). These results reveal that compound 4 can be used as a potent and selective inhibitor for probing the role of nOGA in biological systems.
authors.affiliation: College of Pharmacy, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Li
authors.forename: Tiehai
authors.initials: T
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lina
authors.initials: L
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
mesh_terms: D000117:Acetylglucosamine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001665:Binding Sites; D053148:Caspase 3 / Q000378:metabolism*; D020134:Catalytic Domain; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D054818:Hexosaminidase A / Q000378:metabolism; D054819:Hexosaminidase B / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D010091:Oximes / Q000737:chemistry / Q000494:pharmacology; D048448:Phenylcarbamates / Q000737:chemistry / Q000494:pharmacology; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D014230:Triazoles / Q000737:chemistry / Q000494:pharmacology*; D001619:beta-N-Acetylhexosaminidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: C574754:4-pyridyl-1-(2'-deoxy-2'-acetamidoglucopyranosyl)-1,2,3-triazole; D004791:Enzyme Inhibitors; D010091:Oximes; D048448:Phenylcarbamates; D020033:Protein Isoforms; D011994:Recombinant Proteins; D014230:Triazoles; C068836:N-acetylglucosaminono-1,5-lactone O-(phenylcarbamoyl)oxime; C110628:hexosaminidase C; D054818:Hexosaminidase A; D054819:Hexosaminidase B; D001619:beta-N-Acetylhexosaminidases; D053148:Caspase 3; D000117:Acetylglucosamine