Two distinct enzymes contribute to biphasic S6 phosphorylation in serum-stimulated chicken embryo fibroblasts.
AUTOR(ES)
Sweet, L J
RESUMO
Serum stimulation of quiescent chicken embryo fibroblasts resulted in a time-dependent, biphasic activation of S6 kinase activity. Chromatographic fractionation of serum-stimulated cell lysates resolved two distinct S6 kinase activities. Anti-Xenopus S6 kinase II antiserum immunoprecipitated a 90,000-Mr S6 kinase but did not cross-react with a smaller, 65,000-Mr S6 kinase. Phosphopeptide analysis confirmed that the 90,000- and 65,000-Mr proteins were structurally unrelated and established that the 65,000-Mr protein isolated by the current protocol was the same serum-stimulated chicken embryo fibroblast S6 kinase as that previously characterized (J. Blenis, C. J. Kuo, and R. L. Erikson, J. Biol. Chem. 262:14373-14376, 1987). These results demonstrate the contribution of two distinct S6 kinases to total serum-stimulated ribosomal protein S6 phosphorylation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=360639Documentos Relacionados
- The serum response factor is extensively modified by phosphorylation following its synthesis in serum-stimulated fibroblasts.
- Phosphorylation of ribosomal protein S6 in avian sarcoma virus-transformed chicken embryo fibroblasts.
- Activation of a muscle-specific actin gene promoter in serum-stimulated fibroblasts.
- Regulation of histone mRNA production and stability in serum-stimulated mouse 3T6 fibroblasts.
- Antibodies to Xenopus egg S6 kinase II recognize S6 kinase from progesterone- and insulin-stimulated Xenopus oocytes and from proliferating chicken embryo fibroblasts.
