title: Small-molecule activators of a proenzyme.
abstract: Virtually all of the 560 human proteases are stored as inactive proenyzmes and are strictly regulated. We report the identification and characterization of the first small molecules that directly activate proenzymes, the apoptotic procaspases-3 and -6. It is surprising that these compounds induce autoproteolytic activation by stabilizing a conformation that is both more active and more susceptible to intermolecular proteolysis. These procaspase activators bypass the normal upstream proapoptotic signaling cascades and induce rapid apoptosis in a variety of cell lines. Systematic biochemical and biophysical analyses identified a cluster of mutations in procaspase-3 that resist small-molecule activation both in vitro and in cells. Compounds that induce gain of function are rare, and the activators reported here will enable direct control of the executioner caspases in apoptosis and in cellular differentiation. More generally, these studies presage the discovery of other proenzyme activators to explore fundamental processes of proenzyme activation and their fate-determining roles in biology.
authors.affiliation: Department of Pharmaceutical Chemistry, University of California, San Francisco, Byers Hall, 1700 4th Street, San Francisco, CA 94158, USA.
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Wolan
authors.forename: Julie A
authors.initials: JA
authors.lastname: Zorn
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Gray
authors.forename: James A
authors.initials: JA
authors.lastname: Wells
mesh_terms: D000818:Animals; D017209:Apoptosis; D001578:Benzopyrans / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D055162:Biocatalysis; D053148:Caspase 3 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053178:Caspase 6 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D061945:Caspase Inhibitors; D020134:Catalytic Domain; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053804:Granzymes / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D015394:Molecular Structure; D016296:Mutagenesis; D011725:Pyridines / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D015398:Signal Transduction; D054852:Small Molecule Libraries / Q000737:chemistry / Q000378:metabolism
chemical_list: C545223:8-methoxy-2-oxo-2H-chromene-3-carboxylic acid (3-imidazo(1,2-a)pyridin-2-yl-phenyl)amide; D001578:Benzopyrans; D061945:Caspase Inhibitors; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D007093:Imidazoles; D011725:Pyridines; D054852:Small Molecule Libraries; D053804:Granzymes; D053148:Caspase 3; D053178:Caspase 6