AIMS During β-adrenergic receptor (β-AR) stimulation, phosphorylation of cardiomyocyte ryanodine receptors by protein kinases may contribute to an increased diastolic Ca(2+) spark frequency. Regardless of prompt activation of protein kinase A during β-AR stimulation, this appears to rely more on activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), by a not yet identified signal...

Protein-protein interactions are thought to modulate the efficiency and specificity of Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) signaling in specific subcellular compartments. Here we show that the F-actin-binding protein α-actinin targets CaMKIIα to F-actin in cells by binding to the CaMKII regulatory domain, mimicking CaM. The interaction with α-actinin is blocked by CaMKI...

Sergeant, Gerard P., Susumu Ohya, James A. Reihill, Brian A. Perrino, Gregory C. Amberg, Yuji Imaizumi, Burton Horowitz, Kenton M. Sanders, and Sang Don Koh. Regulation of Kv4.3 currents by Ca /calmodulin-dependent protein kinase II. Am J Physiol Cell Physiol 288: C304–C313, 2005. First published September 29, 2004; doi:10.1152/ajpcell.00293.2004.—The voltage-dependent K channel 4.3 (Kv4.3) is ...

AIMS The anticancer drug paclitaxel (TXL) that polymerizes microtubules is associated with arrhythmias and sinus node dysfunction. TXL can alter membrane expression of Na channels (NaV1.5) and Na current (INa), but the mechanisms are unknown. Calcium/calmodulin-dependent protein kinase II (CaMKII) can be activated by β-adrenergic stimulation and regulates INa gating. We tested whether TXL inter...

Stuck on a channel ctive Ca 2 channels, according to Hudmon et al. (page 537), get their own dedicated Ca 2 sensors that cause well-used channels to open with gusto. Some Ca 2 channels, including voltage-gated L-type channels, let through more Ca 2 per opening when they are used frequently. This positive feedback, known as facilitation, allows fast-beating cardiac cells, for instance, to beat h...

Spontaneous beating of the heart pacemaker, the sinoatrial node, is generated by sinoatrial node cells (SANC) due to gradual change of the membrane potential called diastolic depolarization (DD). Spontaneous, submembrane local Ca(2+) releases (LCR) from ryanodine receptors (RyR) occur during late DD and activate an inward Na(+)/Ca(2+)exchange current to boost the DD rate and fire an action pote...

Purpose: Calcium/calmodulin-dependent kinase II (CaMKII) is involved in the regulation of cell proliferation. Its endogenous inhibitor (hCaKIINa) is expressed in some cell types. We determined the role of CaMKII in RET-stimulated proliferation and hCaMKIINa in medullary thyroid carcinoma (MTC). Experimental Design: We analyzed the role of RET mutants on CaMKII activation in NIH3T3 and in MTC ce...

bstract—We found that a single week of exercise enhanced ognitive function on the Morris water maze (MWM), such hat exercise animals were significantly better than sedentary ontrols at learning and recalling the location of the platform. n order to elucidate the role that calcium calmodulin protein inase II (CAMKII) holds in mediating the exercise-induced nhancement in learning and memory, a sp...

BACKGROUND Digitalis-induced Na(+) accumulation results in an increase in Ca(2+)(i) via the Na(+)/Ca(2+) exchanger, leading to enhanced sarcoplasmic reticulum (SR) Ca(2+) load, responsible for the positive inotropic and toxic arrhythmogenic effects of glycosides. A digitalis-induced increase in Ca(2+)(i) could also activate calcium-calmodulin kinase II (CaMKII), which has been shown to have pro...

The cardiac ryanodine receptor (RyR2)/calcium release channel on the sarcoplasmic reticulum is required for muscle excitation-contraction coupling. Using site-directed mutagenesis, we identified the specific Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylation site on recombinant RyR2, distinct from the site for protein kinase A (PKA) that mediates the "fight-or-flight" stress r...