Cardiac small conductance Ca2+-activated K+ channel subunits form heteromultimers via the coiled-coil domains in the C termini of the channels.

Cardiac Small Conductance Ca -Activated K Channel Subunits Form Heteromultimers via the Coiled-Coil Domains in the C Termini of the Channels

Molecular Medicine Cardiac Small Conductance Ca -Activated K Channel Subunits Form Heteromultimers via the Coiled-Coil Domains in the C Termini of the Channels

Rationale: Ca 2؉-activated K ؉ channels are present in a wide variety of cells. We have previously reported the presence of small conductance Ca 2؉-activated K ؉ (SK or K Ca) channels in human and mouse cardiac myocytes that contribute functionally toward the shape and duration of cardiac action potentials. Three isoforms of SK channel subunits (SK1, SK2, and SK3) are found to be expressed. Mor...

Organization and regulation of small conductance Ca2+-activated K+ channel multiprotein complexes.

Small conductance Ca2+-activated K+ channels (SK channels) are complexes of four alpha pore-forming subunits each bound by calmodulin (CaM) that mediate Ca2+ gating. Proteomic analysis indicated that SK2 channels also bind protein kinase CK2 (CK2) and protein phosphatase 2A (PP2A). Coexpression of SK2 with the CaM phosphorylation surrogate CaM(T80D) suggested that the apparent Ca2+ sensitivity ...

Protein Kinase CK2 Is Coassembled with Small Conductance Ca2+-Activated K+ Channels and Regulates Channel Gating

Small conductance Ca(2+)-activated K+ channels (SK channels) couple the membrane potential to fluctuations in intracellular Ca2+ concentration in many types of cells. SK channels are gated by Ca2+ ions via calmodulin that is constitutively bound to the intracellular C terminus of the channels and serves as the Ca2+ sensor. Here we show that, in addition, the cytoplasmic N and C termini of the c...

A molecular study on the endoplasmic reticulum potassium channels in hepatocytes

Introduction: It has recently been suggested that the KATP channel subunits Kir6.x and BKCa channels exist in the endoplasmic reticulum of cardiomyocytes and neurons. Our previous studies showed the electrophysiological behavior of cation channels in the rough endoplasmic reticulum (RER) of rat hepatocytes. Therefore, we hypothesized that KATP channels and Ca2+-activated potassium channels m...