ABCD2

ABCD2, or ATP-binding cassette subfamily D member 2, is a peroxisomal membrane protein encoded by the ABCD2 gene in humans. It is a member of the ATP-binding cassette transporter family and is expressed in several tissues, with notable levels in liver, brain, kidney, and adrenal tissues.

Functionally, ABCD2 participates in the transport of very long-chain fatty acyl-CoA esters into peroxisomes for beta-oxidation. As with other ABCD transporters, it is thought to operate as an ATP-dependent transporter that uses energy from ATP hydrolysis at cytosolic nucleotide-binding domains to move substrates across the peroxisomal membrane. ABCD2 may form homo- or heterodimers with related transporters such as ABCD1 or ABCD3, contributing to the broader machinery of peroxisomal fatty acid metabolism.

Genetically and clinically, pathogenic variants in ABCD2 have not been definitively linked to a distinct human disease. Some studies in model systems suggest that ABCD2 can partially compensate for ABCD1 deficiency in certain contexts, reflecting functional redundancy within the subfamily. However, the exact contribution of ABCD2 to human peroxisomal metabolism remains to be fully clarified, and more research is needed to establish clinical significance.

In terms of evolution and structure, ABCD2 is conserved across vertebrates and shares the characteristic domain architecture of peroxisomal ABC transporters, including two nucleotide-binding domains and transmembrane segments. Its precise substrate specificity and regulatory mechanisms continue to be active areas of study.