Open AccessAtT20 Cells Express Modified Forms of pp60c–src
Author(s) -
Kathleen L. Gould,
Louise M. Bilezikjian,
Tony Hunter
Publication year - 1989
Publication title -
molecular endocrinology
Language(s) - Uncategorized
Resource type - Journals
eISSN - 1944-9917
pISSN - 0888-8809
DOI - 10.1210/mend-3-1-79
Subject(s) - proto oncogene tyrosine protein kinase src , biology , fibroblast , microbiology and biotechnology , cell culture , phosphorylation , 3t3 cells , in vitro , biochemistry , transfection , genetics
We have compared the properties of pp60c-src from the mouse pituitary tumor cell line, AtT20, and from mouse fibroblasts. In vitro, pp60c-src phosphotransferase activity from AtT20 cells is 2- to 3-fold that of mouse NIH 3T3 fibroblast pp60c-src. In analyzing the reason for this elevation in specific activity, we found that pp60c-src from AtT20 cells differs structurally in at least three ways from pp60c-src in fibroblasts. First, AtT20 cells and primary rat anterior pituitary cells express low levels of the neuronal form of pp60c-src. Second, pp60c-src from AtT20 cells is phosphorylated at two additional N-terminal serine residues. Last, AtT20 pp60c-src is phosphorylated to a lower overall stoichiometry.