Cell-cell contact promotes specific activity of pp60c-src protein kinase in human retinoblastoma cells.
Tyrosine-specific protein kinase activity of pp60c-src was examined in human Y79 retinoblastoma cells cultured in monolayers after clusters in suspension culture had been dissociated. The activity increased five- to six-fold between Days 1 and 7 in the monolayer cultures, with a concomitant increase in numbers of cellular contacts per cell. There was no effect of conditioned medium from high-density cultures in suspension on the activity of cultures with a low degree of contacts. The level of c-src protein in cell lysates was nearly constant irrespective of the degree of cellular contacts. These results suggest that the specific activity of pp60c-src is regulated by cell-cell contact.
Department of Biochemistry, Yamanashi Medical College, Japan.
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Kato
D002450:Cell Communication; D002452:Cell Count; D002455:Cell Division; D002999:Clone Cells; D006801:Humans; D007365:Intercellular Junctions / Q000648:ultrastructure; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src); D012175:Retinoblastoma; D014407:Tumor Cells, Cultured
D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)