Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 (KCNJ11) Antibody – Rabbit Polyclonal

Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, is controlled by G-proteins and is found associated with the sulfonylurea receptor SUR. Mutations in this gene are a cause of familial persistent hyperinsulinemic hypoglycemia of infancy (PHHI), an autosomal recessive disorder characterized by unregulated insulin secretion. Defects in this gene may also contribute to autosomal dominant non-insulin-dependent diabetes mellitus type II (NIDDM), transient neonatal diabetes mellitus type 3 (TNDM3), and permanent neonatal diabetes mellitus (PNDM). Multiple alternatively spliced transcript variants that encode different protein isoforms have been described for this gene. [provided by RefSeq, Oct 2009]

Kir6.2: This receptor is controlled by G proteins. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by extracellular barium. Subunit of ATP-sensitive potassium channels (KATP). Can form cardiac and smooth muscle-type KATP channels with ABCC9. KCNJ11 forms the channel pore while ABCC9 is required for activation and regulation. Defects in KCNJ11 are the cause of familial hyperinsulinemic hypoglycemia type 2 (HHF2); also known as persistent hyperinsulinemic hypoglycemia of infancy (PPHI) or congenital hyperinsulinism. HHF is the most common cause of persistent hypoglycemia in infancy and is due to defective negative feedback regulation of insulin secretion by low glucose levels. It causes nesidioblastosis, a diffuse abnormality of the pancreas in which there is extensive, often disorganized formation of new islets. Unless early and aggressive intervention is undertaken, brain damage from recurrent episodes of hypoglycemia may occur. Defects in KCNJ11 are a cause of diabetes mellitus permanent neonatal (PNDM). PNDM is a rare form of diabetes distinct from childhood-onset autoimmune diabetes mellitus type 1. It is characterized by insulin-requiring hyperglycemia that is diagnosed within the first months of life. Permanent neonatal diabetes requires lifelong therapy. Defects in KCNJ11 are the cause of transient neonatal diabetes mellitus type 3 (TNDM3). Neonatal diabetes mellitus, defined as insulin-requiring hyperglycemia within the first month of life, is a rare entity. In about half of the neonates, diabetes is transient and resolves at a median age of 3 months, whereas the rest have a permanent form of diabetes. In a significant number of patients with transient neonatal diabetes mellitus, diabetes type 2 appears later in life. The onset and severity of TNDM3 is variable with childhood-onset diabetes, gestational diabetes or adult-onset diabetes described. Defects in KCNJ11 may contribute to non-insulin- dependent diabetes mellitus (NIDDM), also known as diabetes mellitus type 2. Belongs to the inward rectifier-type potassium channel (TC 1.A.2.1) family. KCNJ11 subfamily.

Protein type: Channel, potassium; Membrane protein, multi-pass; Membrane protein, integral

Chromosomal Location of Human Ortholog: 11p15.1

Cellular Component: voltage-gated potassium channel complex; mitochondrion; integral to plasma membrane; endoplasmic reticulum; T-tubule; ATP-sensitive potassium channel complex; nuclear envelope; axolemma; cytosol; cell soma; plasma membrane; myelin sheath; endosome

Molecular Function: potassium ion binding; protein C-terminus binding; voltage-gated potassium channel activity; G-protein activated inward rectifier potassium channel activity; heat shock protein binding; ATP-activated inward rectifier potassium channel activity; ankyrin binding; ATP binding

Biological Process: response to drug; synaptic transmission; regulation of membrane potential; potassium ion import; energy reserve metabolic process; glucose metabolic process; response to testosterone stimulus; regulation of insulin secretion; response to estradiol stimulus; response to ATP; negative regulation of insulin secretion; neurological system process

Disease: Maturity-onset Diabetes Of The Young, Type 13; Hyperinsulinemic Hypoglycemia, Familial, 2; Diabetes Mellitus, Transient Neonatal, 3; Diabetes Mellitus, Permanent Neonatal; Diabetes Mellitus, Noninsulin-dependent