OSBPL3

This gene encodes 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. The encoded protein is involved in the regulation of cell adhesion and organization of the actin cytoskeleton. Alternative splicing results in multiple transcript variants.

Full Name

Oxysterol Binding Protein Like 3

Function

Phosphoinositide-binding protein which associates with both cell and endoplasmic reticulum (ER) membranes (PubMed:16143324).
Can bind to the ER membrane protein VAPA and recruit VAPA to plasma membrane sites, thus linking these intracellular compartments (PubMed:25447204).
The ORP3-VAPA complex stimulates RRAS signaling which in turn attenuates integrin beta-1 (ITGB1) activation at the cell surface (PubMed:18270267, PubMed:25447204).
With VAPA, may regulate ER morphology (PubMed:16143324).
Has a role in regulation of the actin cytoskeleton, cell polarity and cell adhesion (PubMed:18270267).
Binds to phosphoinositides with preference for PI(3,4)P2 and PI(3,4,5)P3 (PubMed:16143324).
Also binds 25-hydroxycholesterol and cholesterol (PubMed:17428193).

Biological Process

Bile acid biosynthetic processTAS:Reactome

Cellular Location

Endoplasmic reticulum membrane
Cytoplasm, cytosol
Cell membrane
Cell projection, filopodium tip
Nucleus membrane
Co-localizes with OSBPL6 at contact sites between the plasma membrane and the endoplasmic reticulum.

PTM

Phosphorylation is enhanced in vitro by phorbol-12-myristate-13-acetate (PMA), forskolin and calcium ionophore A23187 (PubMed:25447204).
Phosphorylation seems to be stimulated in conditions of low cell-cell (or cell-matrix) adhesion (PubMed:18270267).