Degradation of focal adhesion proteins paxillin and p130cas by caspases or calpains in apoptotic rat-1 and L929 cells.
Immunofluorescence microscopy revealed the rearrangement and gradual dissociation of paxillin from focal adhesion sites during apoptosis. In vitro, cleavage of paxillin by caspase-3 generated a 42-kDa fragment, among other products, while cleavage by calpain generated a different set of fragments. In Rat-1 cells, cleavage of paxillin by caspase-3 was suppressed by zVAD-fmk or zDEVD-cmk, making caspase-3 a likely executioner during etoposide-induced apoptosis. In contrast, the cleavage of paxillin and p130cas in apoptotic L929 cells was blocked by calpain-specific inhibitors, which also reduced the death rate by 23 to 44%. Therefore, The disassembly and degradation of p130cas and paxillin during apoptosis may controlled by both caspases and calpains, depending upon their cellular contexts. Our findings also suggest that focal adhesion proteins paxillin and p130cas take part in integrin-mediated signaling for cell survival, and that their cleavage by caspase and/or calpain may not only disrupt focal adhesion complexes, but may also impede cell survival signaling.
Shim
S R
SR
Department of Life Science, Kwangju Institute of Science and Technology, Kwangju, 500-712, Korea.
Kook
S
S
Kim
J I
JI
Song
W K
WK
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D002154:Calpain / Q000502:physiology*; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000502:physiology*; D002460:Cell Line; D050719:Crk-Associated Substrate Protein; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000276:immunology / Q000378:metabolism*; D005047:Etoposide / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D022001:Focal Adhesions / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D051419:Paxillin; D010750:Phosphoproteins / Q000276:immunology / Q000378:metabolism*; D011506:Proteins; D051381:Rats; D050717:Retinoblastoma-Like Protein p130; D014407:Tumor Cells, Cultured
D000590:Amino Acid Chloromethyl Ketones; C493843:Bcar1 protein, rat; D061945:Caspase Inhibitors; D050719:Crk-Associated Substrate Protein; D015853:Cysteine Proteinase Inhibitors; D003598:Cytoskeletal Proteins; D009842:Oligopeptides; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; C496063:Pxn protein, rat; D050717:Retinoblastoma-Like Protein p130; C120992:benzyloxycarbonyl aspartyl-glutamyl-valyl-aspartyl-chloromethyl ketone; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D005047:Etoposide; D002154:Calpain; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases