SCP2
Function
Isoform SCPx
Plays a crucial role in the peroxisomal oxidation of branched-chain fatty acids (PubMed:10706581). Catalyzes the last step of the peroxisomal beta-oxidation of branched chain fatty acids and the side chain of the bile acid intermediates di- and trihydroxycoprostanic acids (DHCA and THCA) (PubMed:10706581). Also active with medium and long straight chain 3-oxoacyl-CoAs. Stimulates the microsomal conversion of 7-dehydrocholesterol to cholesterol and transfers phosphatidylcholine and 7-dehydrocholesterol between membrances, in vitro (By similarity). Isoforms SCP2 and SCPx cooperate in peroxisomal oxidation of certain naturally occurring tetramethyl-branched fatty acyl-CoAs (By similarity).
Isoform SCP2
Mediates the transfer of all common phospholipids, cholesterol and gangliosides from the endoplasmic reticulum to the plasma membrane. May play a role in regulating steroidogenesis (PubMed:17157249, PubMed:7642518, PubMed:8300590). Stimulates the microsomal conversion of 7-dehydrocholesterol to cholesterol (By similarity). Also binds fatty acids and fatty acyl Coenzyme A (CoA) such as phytanoyl-CoA. Involved in the regulation phospholipid synthesis in endoplasmic reticulum enhancing the incorporation of exogenous fatty acid into glycerides. Seems to stimulate the rate-limiting step in phosphatidic acid formation mediated by GPAT3. Isoforms SCP2 and SCPx cooperate in peroxisomal oxidation of certain naturally occurring tetramethyl-branched fatty acyl-CoAs (By similarity).
Involvement in disease
Leukoencephalopathy with dystonia and motor neuropathy
LKDMN
A syndrome characterized by leukoencephalopathy, dystonic head tremor, spasmodic torticollis and reduced tendon reflexes in lower extremities. Additional features include hyposmia, pathologic saccadic eye movements, a slight hypoacusis, accumulation of branched-chain pristanic acid in plasma, and the presence of abnormal bile alcohol glucuronides in urine.
None
The disease is caused by variants affecting the gene represented in this entry.
Expression at protein level is almost abolished in Zellweger syndrome. Cholesterol transfer from the endoplasmic reticulum to the plasma membrane was reduced in patient fibroblasts compared to controls.
Post-translational modifications
Isoform SCP2
preSCP2, a protein with a molecular mass of about 15 kDa, is processed into its mature form (SCP2) by proteolytic cleavage of a 20 residue leader sequence after translocation into peroxisomes.
Sequence Similarities
In the N-terminal section; belongs to the thiolase-like superfamily. Thiolase family.
Tissue Specificity
Liver, fibroblasts, and placenta.
Cellular localization
- Isoform SCP2
- Peroxisome
- Cytoplasm
- Mitochondrion
- Endoplasmic reticulum
- Mitochondrion
- Isoform SCPx
- Peroxisome
Alternative names
Sterol carrier protein 2, SCP-2, Acetyl-CoA C-myristoyltransferase, Non-specific lipid-transfer protein, Propanoyl-CoA C-acyltransferase, SCP-2/3-oxoacyl-CoA thiolase, SCP-2/thiolase, SCP-chi, SCPX, Sterol carrier protein X, NSL-TP, SCP-X, SCP2