Lipid transporter involved in lipid countertransport between the endoplasmic reticulum and the plasma membrane: specifically exchanges phosphatidylserine with phosphatidylinositol 4-phosphate (PI4P), delivering phosphatidylserine to the plasma membrane in exchange for PI4P, which is degraded by the SAC1/SACM1L phosphatase in the endoplasmic reticulum. Binds phosphatidylserine and PI4P in a mutually exclusive manner (PubMed:23934110, PubMed:26206935). May cooperate with NPC1 to mediate the exit of cholesterol from endosomes/lysosomes (PubMed:21220512). Binds 25-hydroxycholesterol and cholesterol (PubMed:17428193). {ECO:0000269|PubMed:17428193, ECO:0000269|PubMed:21220512, ECO:0000269|PubMed:23934110, ECO:0000269|PubMed:26206935}. This is the function of Ensembl gene identifier ENSG00000021762 (OSBPL5, oxysterol binding protein like 5).