Phosphorylation-dependent cleavage of p130cas in apoptotic rat-1 cells.
We previously demonstrated caspase-mediated cleavage of p130cas during apoptosis and identified two caspase-3 cleavage sites [1]. In this study, we investigated the phosphorylation-dependent cleavage of p130cas in apoptotic Rat-1 fibroblast cells. Lysophosphatidic acid and fibronectin induced p130cas phosphorylation, which in turn resulted in resistance to caspase-mediated cleavage. Alternatively, dephosphorylation by calf intestinal alkaline phosphatase, PP1, and LAR stimulated cleavage of p130cas by caspase-3, generating a 31-kDa fragment. During apoptosis, p130cas dephosphorylation seems to precede its cleavage. The phosphorylation of tyrosine and serine residues immediately adjacent to the two cleavage sites (DVPD(416) and DSPD(748)) strongly affected p130cas cleavage by caspase-3, both in vitro and in vivo. Furthermore, the generation of the 31-kDa cleavage fragment was strongly regulated by phosphorylation of a tyrosine residue at position 751 (DSPD(748) and GQY(751)). Our results collectively suggest that degradation of p130cas during apoptosis is modulated in a phosphorylation-dependent manner.
Hoon Kim
Do
D
Department of Life Science, Kwangju Institute of Science and Technology, 1 Oryong-dong, Puk-gu, South Korea.
Jeon Choi
Soo
S
Kook
Seunghyi
S
Kim
Wook
W
Keun Song
Woo
W
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D050719:Crk-Associated Substrate Protein; D005047:Etoposide / Q000494:pharmacology; D066298:In Vitro Techniques; D016297:Mutagenesis, Site-Directed; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011506:Proteins; D051381:Rats; D050717:Retinoblastoma-Like Protein p130
C493843:Bcar1 protein, rat; D050719:Crk-Associated Substrate Protein; D010750:Phosphoproteins; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D005047:Etoposide; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases