Sterol carrier protein 2 (SCP2)

Sterol carrier protein 2 (SCP2) is a small, highly conserved, ubiquitous intracellular lipid-binding/transfer protein that mediates the transport of cholesterol, phospholipids, and fatty acids between cellular compartments, facilitating key steps in lipid metabolism and steroid biosynthesis[1][2][3][4]. Encoded by the SCP2 gene, it gives rise to both SCP2 (primarily a lipid transfer protein) and SCPx (which has an additional peroxisomal thiolase enzyme domain), through differential promoter usage and alternative splicing[1][2]. SCP2 is essential for intracellular cholesterol trafficking—particularly in steroidogenic tissues such as Leydig cells during testosterone biosynthesis—and is targeted mainly to peroxisomes, but can also be found in other organelles such as mitochondria, endoplasmic reticulum, and cytosol[2][4]. Deficiency of SCP2 or SCPx results in disrupted lipid transport, abnormal cholesterol/fatty acid metabolism, and it is implicated in disorders such as Zellweger syndrome and hepatic carcinoma in animal models[1][2][3]. SCP2 interacts with proteins including Caveolin-1 and peroxisomal receptor PEX5[1]. No approved drugs directly target SCP2, but fluorescent cholesterol analogs are used experimentally to investigate its function[2].

Other names

SCP2Sterol carrier protein 2SCP-2Non-specific lipid-transfer proteinPropanoyl-CoA C-acyltransferaseSterol carrier protein X (SCPx / SCP-X / SCPX)3-oxoacyl-CoA thiolaseAcetyl-CoA C-myristoyltransferaseNLTPNSL-TPSCOXSCP-CHIEpididymis secretory sperm binding proteinStraight-chain acyl-CoA oxidase

SCP2 facilitates nonvesicular transfer of cholesterol, fatty acids, and phospholipids within cells. SCP2/SCPx helps move cholesterol/fatty acids between intracellular compartments (endoplasmic reticulum, peroxisomes, mitochondria, plasma membrane).