Phosphoinositides are not phosphorylated by the very active tyrosine protein kinase from the murine lymphoma LSTRA.

We studied the ability to phosphorylate phosphoinositides by 3 different subcellular preparations, and immunopurified tyrosine protein kinase (TPK) from two murine lymphoma cell lines induced by the Moloney murine leukemia virus: LSTRA with a very active TPK and MBL2 without significant TPK activity. We could not find any difference in the phosphorylation of phosphoinositides by these preparations. The TPK purified with two antibodies which phosphorylate actively tyrosine on exogenous substrate were unable to phosphorylate phosphoinositides.