Open AccessPhosphorylation of ribosomal protein S6 in avian sarcoma virus-transformed chicken embryo fibroblasts.
Author(s) -
Stuart J. Decker
Publication year - 1981
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.78.7.4112
Subject(s) - ribosomal protein s6 , phosphorylation , biology , microbiology and biotechnology , ribosomal protein , phosphoserine , embryo , virus , mutant , epidermal growth factor , protein phosphorylation , cell culture , biochemistry , virology , rna , ribosome , protein kinase a , serine , gene , genetics
Protein phosphorylation was examined in whole cell extracts from normal and avian sarcoma virus-transformed chicken embryo fibroblasts. The addition of serum or epidermal growth factor to serum-starved normal cells resulted in increased 32P labeling of a Mr 30,000 protein. In extracts from cells transformed by a temperature-sensitive mutant of Schmidt-Ruppin virus, subgroup A, and grown at the permissive temperature, the protein was phosphorylated regardless of serum starvation. This Mr 30,000 protein was shown to be ribosomal protein S6, and the effects of avian sarcoma virus transformation on S6 phosphorylation were further investigated. The ability to phosphorylate S6 in the absence of serum was found to be temperature sensitive when S6 preparations from the temperature-sensitive mutant-infected cells incubated at permissive and nonpermissive temperatures were compared. Cells transformed by the parent virus (Schmidt-Ruppin, subgroup A) maintained the ability to phosphorylate S6 in the absence of serum when incubated at either temperature. Phosphoserine was the only phospho-amino acid detected in acid hydrolysates from phosphorylated S6 preparations.