Phosphatidylinositol Transfer Protein Alpha (PITPNa)

PITPNa encodes a member of a family of lipid-binding proteins that transfer molecules of phosphatidylinositol or phosphatidylcholine between membrane surfaces. The protein is implicated in phospholipase C signaling and in the production of phosphatidylinositol 3,4,5-trisphosphate (PIP3) by phosphoinositide-3-kinase.

PITPN is identical to priming-specific factor-3, one of the 3 priming factors involved in the ATP-dependent priming of Ca(2+)-activated secretion. Rat PITPN shares 40% amino acid homology over its entire length with the Drosophila retinal degeneration B (rdgB) protein. Flies carrying the rdgB mutation undergo light-enhanced retinal degeneration.