Portal de Periódicos da CAPES

Role of MAPK p38α in Hsp90-Induced Cell Death

2007; Elsevier BV; Volume: 13; Issue: 6 Linguagem: Inglês

10.1016/j.cardfail.2007.06.432

1532-8414

Asuka Ota, Yibin Wang,

Computational Drug Discovery Methods

p38α is one of well studied stress-induced protein kinases that allows cells to respond various stressors by transducing extracellular signals to the nucleus. Its activity has been associated with diverse cellular functions and cardimyopathy. In order to investigate p38α pathway in cardiomyocytes, FLAG-DNp38α protein complex from mice heart was co-immunoprecipitated using sepharose beads conjugated with anti-FLAG M2 antibody. Precipitated proteins were trypsinized and identified by LC/MS/MS. Included in the list of identified proteins were heat shock protein 90 (Hsp90), which has been implicated in cardioprotection by several, and its co-chaperonin, Cdc37. The novel interaction between p38α, Hsp90, and Cdc37 was confirmed by co-immunoprecipitation followed by western blot both in vivo and in vitro. Interestingly, pharmacological inhibition of Hsp90 by geldanamycin led to rapid activation of p38α and its downstream signaling proteins. Furthermore, cell death induced by Hsp90 inhibition was delayed in the presence of DNp38α in neonatal cardiomyocytes. Since DNp38α appears to bind more efficiently to Hsp90-Cdc37 chaperone complex than WT p38α, it can be hypothesized that Hsp90 creates a pool of inactive p38α within cardiomyoyte to allow localized activation of p38α in response to stressors. p38α is one of well studied stress-induced protein kinases that allows cells to respond various stressors by transducing extracellular signals to the nucleus. Its activity has been associated with diverse cellular functions and cardimyopathy. In order to investigate p38α pathway in cardiomyocytes, FLAG-DNp38α protein complex from mice heart was co-immunoprecipitated using sepharose beads conjugated with anti-FLAG M2 antibody. Precipitated proteins were trypsinized and identified by LC/MS/MS. Included in the list of identified proteins were heat shock protein 90 (Hsp90), which has been implicated in cardioprotection by several, and its co-chaperonin, Cdc37. The novel interaction between p38α, Hsp90, and Cdc37 was confirmed by co-immunoprecipitation followed by western blot both in vivo and in vitro. Interestingly, pharmacological inhibition of Hsp90 by geldanamycin led to rapid activation of p38α and its downstream signaling proteins. Furthermore, cell death induced by Hsp90 inhibition was delayed in the presence of DNp38α in neonatal cardiomyocytes. Since DNp38α appears to bind more efficiently to Hsp90-Cdc37 chaperone complex than WT p38α, it can be hypothesized that Hsp90 creates a pool of inactive p38α within cardiomyoyte to allow localized activation of p38α in response to stressors.