The death substrate Gas2 binds m-calpain and increases susceptibility to p53-dependent apoptosis.
Gas2 is a caspase-3 substrate that plays a role in regulating microfilament and cell shape changes during apoptosis. Here we provide evidence that overexpression of Gas2 efficiently increases cell susceptibility to apoptosis following UV irradiation, etoposide and methyl methanesulfonate treatments, and that these effects are dependent on increased p53 stability and transcription activity. To investigate possible pathways linking Gas2 to p53, a yeast two-hybrid screen swas performed, indicating m-calpain as a strong Gas2- interacting protein. Moreover, we demonstrate that Gas2 physically interacts with m-calpain in vivo and that recombinant Gas2 inhibits calpain-dependent processing of p53. Importantly, the Gas2 dominant-negative form (Gas2171-314) that binds calpain but is unable to inhibit its activity abrogates Gas2's ability to stabilize p53, to enhance p53 transcriptional activity and to induce p53-dependent apoptosis. Finally, we show that Gas2 is able to regulate the levels of p53 independently of Mdm2 status, suggesting that, like calpastatin, it may enhance p53 stability by inhibiting calpain activity.
Benetti
R
R
Laboratorio Nazionale CIB, Area Science Park, Padriciano 99, 34012 Trieste, Italy.
Del Sal
G
G
Monte
M
M
Paroni
G
G
Brancolini
C
C
Schneider
C
C
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D002154:Calpain / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival; D005047:Etoposide / Q000494:pharmacology; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008840:Microfilament Proteins / Q000378:metabolism*; D012516:Osteosarcoma; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D017384:Sequence Deletion; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D014466:Ultraviolet Rays
C490936:GAS2 protein, human; C099165:Gas2 protein, mouse; D008840:Microfilament Proteins; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; D005047:Etoposide; D008741:Methyl Methanesulfonate; D008156:Luciferases; D002154:Calpain