RESUMO
Phospholipase C-gamma1, containing two SH2 and one SH3 domains which participate in the interaction between signaling molecules, plays a significant role in the growth factor-induced signal transduction. However, the role of the SH domains in the growth factor-induced PLC-gamma1 regulation is unclear. By peptide-mass fingerprinting analysis, we have identified SHIP1 as the binding protein for the SH3 domain of PLC-gamma1. SHIP1 was co-immunoprecipitated with PLC-gamma1 and potentiated EGF-induced PLC-gamma1 activation. However, inositol 5'-phosphatase activity of SHIP1 was not required for the potentiation of EGF-induced PLC-gamma1 activation. Taken together, these results suggest that SHIP1 may function as an adaptor protein which can potentiate EGF-induced PLC-gamma1 activation without regards to its inositol 5'-phosphatase activity.
Assuntos
Animais , Proteínas Adaptadoras de Transdução de Sinal , Sequência de Aminoácidos , Células COS/enzimologia , Chlorocebus aethiops , Ativação Enzimática , Fator de Crescimento Epidérmico/farmacologia , Imunoprecipitação , Inositol 1,4,5-Trifosfato/metabolismo , Dados de Sequência Molecular , Fosfolipases Tipo C/química , Monoéster Fosfórico Hidrolases/química , Ligação Proteica , Transdução de Sinais , Domínios de Homologia de src/fisiologiaRESUMO
Thermoactinomycetes vulgaris is a thermophilic actinomycetes growing optimally at 50 degrees C and Streptomyces albus, S. coelicolor, S. fasciculus and S. olivochromogenes are thermophilically disposed transition species of actinomycetes, which have optimum biomass at 40 degrees C. The acid/alkaline phosphatase and acid/alkaline/neutral protease enzyme from Streptomycetes species showed enzyme activity up to 90 degrees C. In comparison to phosphatases and proteases from T. vulgaris it was concluded that these thermophilically disposed transition species showed macromolecular thermostability i.e. thermostable enzymes and protein.