Studies on the interaction of the human c-myc protein with cell nuclei: p62c-myc as a member of a discrete subset of nuclear proteins.
We have analyzed the localization of the human c-myc product (p62c-myc) at steady state in cells by immunoprecipitation and immunoblotting. We show that p62c-myc is extracted from nuclei by mild salt concentrations (below 200 mM), without affecting gross nuclear structure or causing extraction of major chromatin components. We observe no association between p62c-myc and the nuclear matrix. We also demonstrate that p62c-myc is a member of a discrete subset of nuclear proteins that are all rendered irreversibly insoluble in situ by exposure of isolated nuclei to physiological temperatures (37 degrees C). p62c-myc is sequestered into a similar insoluble complex in cells that have been subjected to heat shock. Finally, we show that avian v-myc and v-myb proteins in isolated nuclei also become insoluble after exposure to temperatures above 37 degrees C. We discuss the possible implications of these results.
D002458:Cell Fractionation; D002460:Cell Line; D002467:Cell Nucleus / Q000032:analysis* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D009856:Oncogene Proteins, Viral / Q000032:analysis; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000378:metabolism; D012995:Solubility; D013347:Subcellular Fractions; D013696:Temperature
D009856:Oncogene Proteins, Viral; D011518:Proto-Oncogene Proteins