OSBP

Oxysterol binding protein is an intracellular protein that is believed to transport sterols from lysosomes to the nucleus where the sterol down-regulates the genes for the LDL receptor, HMG-CoA reductase, and HMG synthetase [provided by RefSeq]

Full Name

oxysterol binding protein

Function

Lipid transporter involved in lipid countertransport between the Golgi complex and membranes of the endoplasmic reticulum: specifically exchanges sterol with phosphatidylinositol 4-phosphate (PI4P), delivering sterol to the Golgi in exchange for PI4P, which is degraded by the SAC1/SACM1L phosphatase in the endoplasmic reticulum (PubMed:24209621).
Binds cholesterol and a range of oxysterols including 25-hydroxycholesterol (PubMed:15746430, PubMed:17428193).
Cholesterol binding promotes the formation of a complex with PP2A and a tyrosine phosphatase which dephosphorylates ERK1/2, whereas 25-hydroxycholesterol causes its disassembly (PubMed:15746430).
Regulates cholesterol efflux by decreasing ABCA1 stability (PubMed:18450749).

Biological Process

Bile acid biosynthetic processTAS:Reactome
Ceramide transportManual Assertion Based On ExperimentIMP:ComplexPortal
Intracellular cholesterol transportManual Assertion Based On ExperimentIMP:UniProtKB
Phospholipid transportManual Assertion Based On ExperimentIDA:ComplexPortal
Positive regulation of insulin secretion involved in cellular response to glucose stimulusIEA:Ensembl
Positive regulation of secretory granule organizationIEA:Ensembl
Positive regulation of tyrosine phosphorylation of STAT proteinIEA:Ensembl
Sphingomyelin biosynthetic processManual Assertion Based On ExperimentIMP:ComplexPortal
Sterol transportManual Assertion Based On ExperimentIDA:UniProtKB

Cellular Location

Cytoplasm, cytosol
Cytoplasm, perinuclear region
Golgi apparatus membrane ; Peripheral membrane protein
Endoplasmic reticulum membrane ; Peripheral membrane protein
Golgi apparatus, trans-Golgi network
Predominantly cytosolic.