Science, Vol 268, Issue 5214, 1188-1190
Copyright © 1995 by American Association for the Advancement of Science
Requirement for phosphatidylinositol transfer protein in epidermal growth factor signaling
A Kauffmann-Zeh,
GM Thomas,
A Ball,
S Prosser,
E Cunningham,
S Cockcroft,
and
JJ Hsuan
Protein Biochemistry Group, Ludwig Institute for Cancer Research, University College London School of Medicine, UK.
Stimulation of phosphatidylinositol-4,5-bisphosphate (PIP2) hydrolysis is a widespread mechanism for receptor-mediated signaling in eukaryotes. Cytosolic phosphatidylinositol transfer protein (PITP) is necessary for guanosine triphosphate (GTP)-dependent hydrolysis of PIP2 by phospholipase C-beta (PLC-beta), but the role of PITP is unclear. Stimulation of phospholipase C-gamma (PLC-gamma) in A431 human epidermoid carcinoma cells treated with epidermal growth factor (EGF) required PITP. Stimulation of PI-4 kinase in cells treated with EGF also required PITP. Coprecipitation studies revealed an EGF-dependent association of PITP with the EGF receptor, with PI-4 kinase, and with PLC-gamma.
