title: Caspase-9 activation and Apaf-1 cleavage by MMP-3.
abstract: We have previously demonstrated that matrix metalloprotease-3 (MMP-3) can act inside the cell to trigger apoptosis in response to various cell stresses in dopaminergic neuronal cells. However, the mechanism by which MMP-3 activity leads to caspase-3 activation in apoptotic signaling was not known. In the present study, we found that MMP-3 acts upstream of caspase-9. Overexpression of wild type MMP-3, but not mutant MMP-3, generated the enzymatically active 35kD caspase-9. The caspase-9 activation was absent in MMP-3 knockout cells, but was present when these cells were transfected with wild type MMP-3 cDNA. It was elevated in cells that were under a MMP-3-inducing ER stress condition, and this was attenuated by pharmacologic inhibition and gene knockdown of MMP-3. Incubation of recombinant catalytic domain of MMP-3 (cMMP-3) with procaspase-9 was not sufficient to cause caspase-9 activation, and an additional cytosolic factor was required. cMMP-3 was found to bind to the cytosolic protein Apaf-1, as determined by changes in surface plasmon resonance, and to cleave Apaf-1. Pharmacological inhibition, knockout, and knockdown of MMP-3 attenuated the cleavage. Taken together, the present study demonstrates that MMP-3 leads to caspase-9 activation and suggests that this occurs indirectly via a cytosolic protein, possibly involving Apaf-1.
authors.affiliation: Department of Emergency Medical Technology, Korea Nazarene University, Cheonan 331-718, South Korea.
authors.forename: Eun-Mee
authors.initials: EM
authors.lastname: Kim
authors.affiliation: Department of Biochemistry and Molecular Biology, Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul 138-736, South Korea.
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Shin
authors.affiliation: Department of Biochemistry and Molecular Biology, Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul 138-736, South Korea.
authors.forename: Ji Ae
authors.initials: JA
authors.lastname: Lee
authors.affiliation: Department of Biochemistry and Molecular Biology, Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul 138-736, South Korea.
authors.forename: Hyo Jin
authors.initials: HJ
authors.lastname: Son
authors.affiliation: Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Konkuk University, Seoul 143-747, South Korea.
authors.forename: Dong Hee
authors.initials: DH
authors.lastname: Choi
authors.affiliation: Department of Biochemistry and Molecular Biology, Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul 138-736, South Korea.
authors.forename: Ji Man
authors.initials: JM
authors.lastname: Han
authors.affiliation: Department of Biochemistry and Molecular Biology, Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul 138-736, South Korea. Electronic address: oyhwang@amc.seoul.kr.
authors.forename: Onyou
authors.initials: O
authors.lastname: Hwang
mesh_terms: D000818:Animals; D017209:Apoptosis; D053477:Apoptotic Protease-Activating Factor 1 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004789:Enzyme Activation; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011485:Protein Binding; D059748:Proteolysis; D015398:Signal Transduction; D013312:Stress, Physiological; D020349:Surface Plasmon Resonance
chemical_list: C506593:Apaf1 protein, mouse; D053477:Apoptotic Protease-Activating Factor 1; D053453:Caspase 9; D019278:Matrix Metalloproteinase 3
keywords: Apaf-1; Apoptosis; Caspase-9; Matrix metalloproteinase-3