Y. Hanazono et al., TYROSINE PHOSPHORYLATION OF THE PROTOONCOGENE PRODUCT VAV AND ITS ASSOCIATION WITH THE ADAPTER GRB2 ASH IN A HUMAN LEUKEMIA-CELL LINE UT-7/, Japanese journal of cancer research, 86(4), 1995, pp. 336-341
The vav proto-oncogene product (Vav) is expressed exclusively in hemat
opoietic cells and is reported to have guanine nucleotide exchange act
ivity. Here we report that granulocyte-macrophage colony-stimulating f
actor, interleukin-3, and erythropoietin induce tyrosine phosphorylati
on of Vav in a human leukemia cell line UT-7. Tyrosine phosphorylation
of Vav is rapid and transient; it occurs within 1 min of the stimulat
ion and at physiological concentrations of the factors. Furthermore, w
e show that Vav is constitutively associated with the adapter molecule
Grb2/Ash in UT-7. These data suggest that tryosine kinases, the adapt
er Grb2/Ash, and the guanine nucleotide exchange factor Vav are member
s of a signaling pathway leading to Ras activation in hematopoietic ce
lls.