Normal c-abl gene protein--a nuclear component.

The subcellular distribution of the c-abl and bcr-abl gene products from KG1A and K562 cells has been studied by two different techniques. Firstly, physical disruption followed by subcellular fractionation was used to demonstrate that normal c-abl (p145) was recovered from the cytosol and the nuclear fractions of KG1A cells. In contrast, bcr-abl products were recovered exclusively from the cytosol fraction of K562 cells. Secondly, indirect immunofluorescence was used to localize c-abl protein to the cytoplasm, nuclear membrane and infrequently to the nucleus of KG1A cells and bcr-abl protein to only the cytoplasm of K562 cells. Thus both the approaches indicate that there is a component of normal c-abl products which appears to be nuclear and this is not reflected in the distribution of the bcr-abl 210 kDa protein, which remains cytosolic.