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 . Binds oxysterol, 25-hydroxycholesterol and cholesterol ( ).
Subcellular locations: Endoplasmic reticulum membrane, Nucleus membrane
The presence of the N-terminus extension contains an overall negative charge that may explain the weak localization to the cortical endoplasmic reticulum (Probable).
Subcellular locations: Endoplasmic reticulum membrane
Localizes to the cortical endoplasmic reticulum at the endoplasmic reticulum-plasma membrane contact sites.
Widely expressed . Expressed at higher level in macrophages .