Nuclear association of tyrosine-phosphorylated Vav to phospholipase C-gamma 1 and phosphoinositide 3-kinase during granulocytic differentiation of HL-60 cells

The granulocytic differentiation of HL-60 cells induced bg all-trans retino ic acid was accompanied by a progressive tyrosine phosphorylation of specif ic proteins in either cells or isolated nuclei. Among these phosphoproteins , we identified the Vav adaptor in whole cells as well as in the inner nucl ear compartment, where the increase in its tyrosine phosphorylation level w as more conspicuous. We also demonstrated the differentiation-dependent ass ociation of nuclear phosphorylated Vav to phospholipase C-gamma 1 and to th e p85 regulatory subunit of phosphoinositide 3-kinase, The role of the Vav/ phospholipase C-gamma 1/phosphoinositide 3-kinase phosphoprotein complexes in the nuclei of HL-60 induced to differentiate along the granulocytic line age is discussed. (C) 1998 Federation of European Biochemical Societies.