Functions as a carrier for hydrophobic molecules in body fluids (Probable). Essential for the solubility and activity of lipidated Wnt family members, including WNT1, WNT2B, WNT3, WNT3A, WNT5A, WNT7A, WNT7B, WNT8, WNT9A, WNT9B, WNT10A and WNT10B (PubMed:26902720). Binds vitamin E (PubMed:12463752, PubMed:15952736). May transport vitamin E in body fluids under conditions where the lipoprotein system is not sufficient (PubMed:15952736). May be involved in the transport of vitamin E across the blood-brain barrier (PubMed:19046407).
