INTERACTION OF PHOSPHOLIPASE-C GAMMA-1 VIA ITS COOH-TERMINAL SRC HOMOLOGY-2 DOMAIN WITH SYNAPTOJANIN

The role of the phospholipase C gamma 1 (PLC gamma 1) in signal transd uction was investigated by characterizing its interactions with protei ns that may represent components of a novel signalling pathway. A 145- kDa protein that binds SH2 domain of PLC gamma 1 was purified from rat brain. The sequence of peptide derived from the purified binding prot ein now identify it as synaptojanin, a nerve terminal protein that has been implicated in the endocytosis of fused synaptic vesicles and sho wn to be a member of the inositol polyphosphate 5-phosphatase family. We demonstrate here stable association of PLC gamma 1 with synaptojani n, a protein that not only binds carboxyl terminal SH2 domain of PLC g amma 1, but also inhibits PLC gamma 1 activity. (C) 1998 Academic Pres s.