K+/Na+ hyperpolarization-activated cyclic nucleotide-gated channel 2; brain cyclic nucleotide-gated channel 2; BCNG-2 (HCN2 BCNG2)

Function: - hyperpolarization-activated ion channel - exhibits weak selectivity for K⁺ over Na⁺ - contributes to native pacemaker currents in heart (If) & in neurons (Ih) - produces a large instantaneous current - activated by cAMP - modulated by intracellular chloride ions & pH; acidic pH shifts activation to more negative voltages (putative) - the K⁺ channel is probably composed of a homo- or heterotetrameric complex of pore-forming subunits - heteromultimer with HCN1 - interacts with KCNE2 (putative) Structure: - the segment S4 is probably the voltage-sensor; it is characterized by a series of positively charged amino acids at every third position - belongs to the K⁺ channel HCN family - contains 1 cyclic nucleotide-binding domain Compartment: membrane Expression: - highly expressed throughout the brain - detected at low levels in heart Notes: - inhibited by extracellular Cs+

General

hyperpolarization-activated cyclic nucleotide gated K+ channel glycoprotein transmembrane 6 protein

Properties

SIZE: entity length = 889 aa MW = 97 kD COMPARTMENT: plasma membrane MOTIF: cytoplasmic domain {1-215} MOTIF: proline-rich region SITE: 10-140 MOTIF: proline residue (SEVERAL) Ser phosphorylation site {S146} Involved in subunit assembly {158-209} transmembrane domain {216-236} exoplasmic loop {237-240} transmembrane domain {241-261} cytoplasmic loop {262-288} transmembrane domain {289-309} exoplasmic loop {310-317} transmembrane domain {318-338} cytoplasmic loop {339-369} transmembrane domain {370-390} exoplasmic loop {391-440} MOTIF: N-glycosylation site {N407} H5 (K+) pore-forming region {414-435} transmembrane domain {441-461} cytoplasmic domain {462-889} MOTIF: cAMP-binding site SITE: 544-661 proline-rich region SITE: 715-861 MOTIF: proline residue (SEVERAL) Ser phosphorylation site {S779} ION-PERMEABILITY: K+

Database Correlations

OMIM 602781 UniProt Q9UL51 PFAM correlations Entrez Gene 610 Kegg hsa:610