p60c-src is complexed with a cellular protein in subcellular compartments involved in exocytosis.
We found high levels of the c-src gene product in neuroendocrine tissues from adult animals. To understand the role of this proto-oncogene product, the subcellular localization of p60c-src was studied in neuroendocrine tissue from adrenal medulla. The results indicate that p60c-src was highly enriched in chromaffin granule membranes, in stable association with a protein of 38 kD. The complex with the 38-kD protein was also detected in brain, a tissue known to carry high levels of p60c-src. The 38-kD protein is not calpactin I, II, or synaptophysin. Comparison of its peptide map showed a high degree of conservation among the different species and tissues examined. The interaction between p60c-src and the 38-kD protein involves disulphide bonds that are stable even when the cell fractionation is performed in the presence of a reducing agent. Since the presence of disulphide bonds among cytoplasmic proteins is very unlikely, the possibility of a noncovalent association between p60c-src and the 38-kD protein in vivo is discussed. The 38-kD protein may be involved in a function of p60c-src related to secretory organelles.
Grandori
C
C
Rockefeller University, New York 10021.
Hanafusa
H
H
D000313:Adrenal Medulla / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000502:physiology / Q000648:ultrastructure; D002417:Cattle; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology; D004220:Disulfides; D005089:Exocytosis; D046911:Macromolecular Substances; D008970:Molecular Weight; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D016392:Proto-Oncogene Proteins pp60(c-src)
D004220:Disulfides; D046911:Macromolecular Substances; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)