SOLVED:Two protein kinases, K 1 and K 2, function sequentially in an intracellular signaling pathway. If either kinase contains a mutation that permanently inactivates its function, no response is seen in cells when an extracellular signal is received. A different mutation in K 1 makes it permanently active, so that in cells containing that mutation a response is observed even in the absence of an extracellular signal. You characterize a double-mutant cell that contains K 2 with the inactivating

Phosphoinositide GPCR Signaling

Phosphatidylinositol Biphosphate (PIP2) Signal Pathway

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay