AtT20 cells express modified forms of pp60c-src.
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.
Gould
K L
KL
Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92138.
Bilezikjian
L M
LM
Hunter
T
T
D000135:Acid Phosphatase / Q000494:pharmacology; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000378:metabolism; D007163:Immunosorbent Techniques; D007526:Isoelectric Point; D051379:Mice; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src); D014407:Tumor Cells, Cultured
D009227:Myristic Acids; D011518:Proto-Oncogene Proteins; D019814:Myristic Acid; D010770:Phosphotransferases; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D000135:Acid Phosphatase