Differential Regulated Interactions of Calcium/Calmodulin-Dependent Protein Kinase II with Isoforms of Voltage-Gated Calcium Channel β Subunits
- 19 January 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 47 (6) , 1760-1767
- https://doi.org/10.1021/bi701755q
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylates the β2a subunit of voltage-gated Ca2+ channels at Thr498 to facilitate cardiac L-type Ca2+ channels. CaMKII colocalizes with β2a in cardiomyocytes and also binds to a domain in β2a that contains Thr498 and exhibits an amino acid sequence similarity to the CaMKII autoinhibitory domain and to a CaMKII binding domain in the NMDA receptor NR2B subunit (Grueter, C. E. et al. (2006) Mol. Cell23, 641). Here, we explore the selectivity of the actions of CaMKII among Ca2+ channel β subunit isoforms. CaMKII phosphorylates the β1b, β2a, β3, and β4 isoforms with similar initial rates and final stoichiometries of 6−12 mol of phosphate per mol of protein. However, activated/autophosphorylated CaMKII binds to β1b and β2a with a similar apparent affinity but does not bind to β3 or β4. Prephosphorylation of β1b and β2a by CaMKII substantially reduces the binding of autophosphorylated CaMKII. Residues surrounding Thr498 in β2a are highly conserved in β1b but are different in β3 and β4. Site-directed mutagenesis of this domain in β2a showed that Thr498 phosphorylation promotes dissociation of CaMKII-β2a complexes in vitro and reduces interactions of CaMKII with β2a in cells. Mutagenesis of Leu493 to Ala substantially reduces CaMKII binding in vitro and in intact cells but does not interfere with β2a phosphorylation at Thr498. In combination, these data show that phosphorylation dynamically regulates the interactions of specific isoforms of the Ca2+ channel β subunits with CaMKII.Keywords
This publication has 37 references indexed in Scilit:
- Calmodulin Kinase II Is Involved in Voltage-dependent Facilitation of the L-type Cav1.2 Calcium ChannelJournal of Biological Chemistry, 2006
- Molecular basis for the modulation of native T-type Ca2+ channels in vivo by Ca2+/calmodulin-dependent protein kinase IIJournal of Clinical Investigation, 2006
- The importance of occupancy rather than affinity of CaVβ subunits for the calcium channel I–II linker in relation to calcium channel functionThe Journal of Physiology, 2006
- Nuclear Sequestration of β-Subunits by Rad and Rem is Controlled by 14-3-3 and Calmodulin and Reveals a Novel Mechanism for Ca2+ Channel RegulationJournal of Molecular Biology, 2006
- The L-type calcium channel in the heart: the beat goes onJournal of Clinical Investigation, 2005
- Essential Cavβ modulatory properties are AID-independentNature Structural & Molecular Biology, 2005
- Structure of a complex between a voltage-gated calcium channel β-subunit and an α-subunit domainNature, 2004
- Targeting of calcium/calmodulin-dependent protein kinase IIBiochemical Journal, 2004
- The carboxyl‐terminal region of ahnak provides a link between cardiac L‐type Ca2+channels and the actinbased cytoskeletonThe FASEB Journal, 2002
- The I-II Loop of the Ca 2+ Channel α 1 Subunit Contains an Endoplasmic Reticulum Retention Signal Antagonized by the β SubunitNeuron, 2000