Immunolocalization of the cellular src protein in interphase and mitotic NIH c-src overexpresser cells.
The mouse mAb, mAb 327, that recognizes specifically both pp60v-src and pp60c-src in a wide variety of cells, has been used to determine precisely the various locations of pp60c-src in NIH c-src overexpresser cells, using the technique of immunofluorescence microscopy. In interphase cells, the protein exhibits two main distributions: one that appears uniform and in association with the cell surface and the other that is patchy and juxtanuclear and coincides with the centrosomes. The juxtanuclear aggregation of pp60c-src-containing patches depends on microtubules and does not seem to occur within the Golgi apparatus and the rough ER. At the G2-to-M-phase transition, a drastic change in the localization patterns of pp60c-src takes place. We also report experiments in which the NIH c-src overexpresser cells were exposed to Con A for various times to induce a redistribution of the cell surface Con A receptors. We show that, at each stage of the Con A-mediated endocytotic process, the Con A-receptor complexes redistribute into structures to which pp60c-src appears also to be associated: at first, into patches that form at the cell surface level and then, into a cap that stands at the cell center in a juxtanuclear position and that coincides with the Golgi apparatus. During this capping process, pp60c-src-containing vesicles continue to accumulate in a centriolar spot, as in interphase, Con A-untreated cells, from which Con A is excluded. The significance of the intracellular locations of pp60c-src to the possible functions of the protein is discussed. Also, the distribution patterns of the cellular protein in the NIH c-src overexpresser cells are compared with those of pp60v-src in RSV-transformed cells. The differences observed are discussed in relation with the differences in transforming capacities of the two proteins. Finally, the possible physiological significance of the association between pp60c-src and the structures generated after the binding of Con A to its surface receptors is addressed.
David-Pfeuty
T
T
Institut Curie-Biologie, Centre Universitaire, Orsay, France.
Nouvian-Dooghe
Y
Y
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002451:Cell Compartmentation; D002460:Cell Line; D003208:Concanavalin A / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology; D005456:Fluorescent Dyes; D007150:Immunohistochemistry; D007399:Interphase / Q000502:physiology*; D008938:Mitosis / Q000502:physiology*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000032:analysis* / Q000502:physiology; D011994:Recombinant Proteins / Q000032:analysis; D014162:Transfection
D005456:Fluorescent Dyes; D011994:Recombinant Proteins; D003208:Concanavalin A; D016392:Proto-Oncogene Proteins pp60(c-src)