It has been shown tht oxogenousty added H2O2 elicits tyrosine phosphorylation of a variety of protine including PLC as well as Ca2+ mobiliza tion in several cell types. We investigated the likage between PLC phosphorylation and CA2+ mobilization in A431 cells. Immunoblot analysis with anti-phospotyrosine antibilization incirated that the tyrosine phosphorylation of PLC peaked within 5 min after H2O 2 treatment and returned to basal level within 30 min. The PLC phosphorylation coincided with the onset of H2O2 treatment and returned to basal level with induced inositol phosphates production Prior incubation of A431 cells with thapsigargin caused a nearly complete inhibition of H2O2-dependent Ca2+ mobilization in the absence of extracellular CA2+. These results suggest that the phospherylation of PLC induced by H2O2 and subsequent product on of In-(1.4.5)P3 are mainly responsible for the CA 2+ mobilization observed in A431 cels stimulated with H 2O2.
|State||Published - 1997|