ATP-sensitive potassium channel regulatory subunit SUR2 (SUR2) (SUR2)

The ATP-sensitive potassium channel regulatory subunit SUR2, encoded by the ABCC9 gene, is a member of the ATP-binding cassette (ABC) transporter superfamily that functions as a key regulator of K_ATP channels (UniProt: P57071). Unlike typical ABC transporters, SUR2 does not transport substrates but instead acts as a metabolic sensor that couples cellular ATP levels to membrane potential in cardiac, skeletal, and smooth muscle cells (PubMed: 10559060). It forms heterooctameric complexes with pore-forming Kir6.1 or Kir6.2 subunits, where its binding of nucleotides or drugs modulates the channel's open-state probability (NCBI Gene: 10060). SUR2 exists in two major isoforms, SUR2A (predominant in the heart) and SUR2B (predominant in vascular smooth muscle), which dictate the pharmacological profile of the channel (StatPearls: Potassium Channel Openers). Mutations in the ABCC9 gene are associated with Cantu syndrome, characterized by hypertrichosis and cardiomegaly, as well as forms of dilated cardiomyopathy (PubMed: 22503633). Therapeutically, SUR2 is targeted by potassium channel openers such as minoxidil and nicorandil to treat hypertension and angina by promoting vasodilation (PubChem: CID 4201). Its role in smooth muscle relaxation makes it a key therapeutic target for cardiovascular disorders.

Other names

Sulfonylurea receptor 2ABCC9ATP-binding cassette sub-family C member 9SUR2ASUR2B

Modulation of K_ATP channel activity by binding to the SUR2 subunit, which induces a conformational change in the pore-forming Kir6.x subunits to either promote (openers) or inhibit (blockers) potassium ion flow (PubMed: 9110111).