ATP-binding cassette sub-family C member 9 (SUR2B) (SUR2B)

The Sulfonylurea receptor 2B (SUR2B) is a specific splice variant of the ABCC9 gene that functions as the essential regulatory subunit of ATP-sensitive potassium (KATP) channels in vascular and non-vascular smooth muscle (UniProt: O60706). These channels are heterooctameric complexes, typically comprising four pore-forming Kir6.1 or Kir6.2 subunits and four SUR2B subunits (PubMed: 9159554). SUR2B plays a pivotal role in sensing the intracellular ATP/ADP ratio, thereby coupling cellular metabolic status to membrane excitability and muscle contractility. Activation of SUR2B-containing channels by potassium channel openers (KCOs) like minoxidil or pinacidil induces membrane hyperpolarization, which leads to vasodilation and reduced peripheral resistance. Mutations in the ABCC9 gene encoding SUR2B are linked to Cantu syndrome, a condition characterized by hypertrichosis, osteochondrodysplasia, and cardiomegaly (PubMed: 25135911). Consequently, SUR2B is a significant therapeutic target for managing hypertension and understanding vascular disorders.

Other names

ABCC9Sulfonylurea receptor 2BSUR2ABC37ATP-binding cassette sub-family C member 9

SUR2B acts as the regulatory subunit of ATP-sensitive potassium (KATP) channels. Potassium channel openers (KCOs) bind to the SUR2B subunit to stabilize the open state of the channel, leading to potassium efflux, membrane hyperpolarization, and relaxation of smooth muscle cells. Conversely, sulfonylureas bind to SUR2B to inhibit channel activity.