Oxysterol-binding protein-related protein 5 (Osbpl5)

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.

May collaborate with NPC1 to mediate the exit of cholesterol from endosomes/lysosomes. Binds 25- hydroxycholesterol and cholesterol.