INTERACTION OF BCR-ABL WITH THE RETINOBLASTOMA PROTEIN IN PHILADELPHIA-CHROMOSOME-POSITIVE CELL-LINES

The tyrosine kinase activity of BCR-ABL fusion proteins plays an impor tant role in the pathogenesis of leukemia that is for the Philadelphia chromosome (Ph(1)). Because nuclear c-ABL is regulated during the cel l cycle through a specific interaction with the retinoblastoma protein (pRB), the possible interaction of BCR-ABL with pRB in Ph(1)-positive cell lines was investigated. P145 c-ABL as well as P190 and P210 BCR- ABL proteins interacted with pRB. Furthermore, c-ABL and BCR-ABL assoc iated with both phosphorylated and nonphosphorylated forms of pRB. The se findings suggest that BCR-ABL interferes with pRB function and ther eby regulates cell growth. (C) 1997 Elsevier Science Ireland Ltd.