UCL Discovery

Abstract

Pitpnc1 (Phosphatidylinositol transfer protein, cytoplasmic 1; also known as RdgBβ) was originally identified by means of its sequence similarity to the phosphatidylinositol transfer protein (PITP) family, whose proteins are encoded by five different genes in mammals: PITPα/Pitpna, PITPβ/Pitpnb, rdgBβ/Pitpnc1, Nir2/rdgB1/Pitpnm1, and Nir3/rdgB2/Pitpnm2. Family members are characterized by a single PITP domain, which can transfer phosphatidylinositol or phosphatidylcholine between lipid membranes. Although functional degeneracy of different family members has been found by using recombinant protein overexpression in vitro or in vivo, the existence of physiological differences in expression and subcellular localization as well as differences in mutant phenotypes indicate specificity of function in vivo. However, molecular mechanisms underlying differential regulation, localization, and function remain largely unknown for most isoforms, including Pitpnc1.