JAK2 IS ASSOCIATED WITH THE C-KIT PROTOONCOGENE PRODUCT AND IS PHOSPHORYLATED IN RESPONSE TO STEM-CELL FACTOR

Stem cell factor (SCF) is a hematopoietic growth factor that interacts with the receptor tyrosine kinase, c-kit. We have found that SCF stim ulates rapid and transient tyrosine phosphorylation of JAK2 in human a nd murine cell lines, as well as in normal human progenitor cells, JAK 2 and c-kit were associated in unstimulated cells with further recruit ment of JAK2 to the c-kit receptor complex after SCF stimulation. Trea tment of cells with JAK2 antisense oligonucleotides resulted in a 46% decrease in SCF-induced proliferation. These data demonstrate that SCF induces tyrosine phosphorylation of JAK2 and suggest that JAK2 is a c omponent of the SCF signal transduction pathway. This is a US governme nt work. There are no restrictions on its use.