The function of OSBPL3 (oxysterol binding protein like 3, ENSG00000070882) is as follows. Lipid transfer protein that mediates the non-vesicular transport of phosphoinositide 4-phosphate (1,2-diacyl-sn-glycero-3- phospho-(1D-myo-inositol 4-phosphate), or PI(4)P) at the plasma membrane (PM)/ endoplasmic reticulum (ER) contact sites (PubMed:16143324, PubMed:32041906, PubMed:32234213). Extracts PI4P from the PM, in exchange for phosphatidylcholine (PubMed:32234213). Can bind to the ER membrane protein VAPA and recruit VAPA to PM sites, thus linking these intracellular compartments (PubMed:25447204). The ORP3- VAPA complex stimulates RRAS signaling which in turn attenuates integrin beta-1 (ITGB1) activation at the cell surface (PubMed:18270267, PubMed:25447204). With VAPA, may regulate ER morphology (PubMed:16143324). Has a role in regulation of the actin cytoskeleton, cell polarity and cell adhesion (PubMed:18270267). Binds to phosphoinositides with preference for PI(3,4)P2 and PI(3,4,5)P3 (PubMed:16143324). Also binds 25-hydroxycholesterol and cholesterol (PubMed:17428193). {ECO:0000269|PubMed:16143324, ECO:0000269|PubMed:17428193, ECO:0000269|PubMed:18270267, ECO:0000269|PubMed:25447204, ECO:0000269|PubMed:32041906, ECO:0000269|PubMed:32234213}.