JAK2 is constitutively associated with c-Kit and is phosphorylated in response to stem cell factor.

Stem cell factor (SCF) interacts with the receptor tyrosine kinase c-Kit and has potent effects on hematopoiesis. We have examined the role of JAK2 in the SCF signal transduction pathway. JAK2 and c-Kit were constitutively associated, and treatment with SCF resulted in rapid and transient tyrosine phosphorylation of JAK2. Incubation of cells with JAK2 antisense oligonucleotides resulted in significant decreases in SCF-induced proliferation. These data suggest that JAK2 plays a role in SCF-induced proliferation.