Oxysterol Binding Protein Like Protein 1A (OSBPL1A)

Oxysterol-binding protein-related protein 1 is a member of the oxysterol-binding protein (OSBP) family, a group of intracellular lipid receptors. Most members contain an N-terminal pleckstrin homology domain and a highly conserved C-terminal OSBP-like sterol-binding domain, although some members contain only the sterol-binding domain. ORP1 encodes a deduced 437-amino acid protein. Yeast complementation assays indicated that ORP1 is a counterpart of yeast Kes1. Fluorescence microscopy demonstrated expression of ORP1 in the cytosol.

Endogenous expression in a neuroblastoma cell line was upregulated by exposure to low density lipoprotein. Similar treatment on a hepatocellular carcinoma cell line did not result in significant alterations in ORP1 mRNA levels.