Differential Regulated Interactions of Calcium/Calmodulin-Dependent Protein Kinase II with Isoforms of Voltage-Gated Calcium Channel 
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- 作者：Chad E. Grueter ; Sunday A. Abiria ; Yunji Wu ; Mark E. Anderson ; Roger J. Colbran
- 刊名：Biochemistry
- 出版年：2008
- 出版时间：February 12, 2008
- 年：2008
- 卷：47
- 期：6
- 页码：1760 - 1767
- 全文大小：331K
- 年卷期：v.47,no.6(February 12, 2008)
- ISSN：1520-4995
文摘
Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylates the 
gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a subunit ofvoltage-gated Ca2+ channels at Thr498 to facilitate cardiac L-type Ca2+ channels. CaMKII colocalizeswith gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a in cardiomyocytes and also binds to a domain in gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a that contains Thr498 and exhibits an aminoacid sequence similarity to the CaMKII autoinhibitory domain and to a CaMKII binding domain in theNMDA receptor NR2B subunit (Grueter, C. E. et al. (2006) Mol. Cell 23, 641). Here, we explore theselectivity of the actions of CaMKII among Ca2+ channel gifchars/beta2.gif" BORDER=0 ALIGN="middle"> subunit isoforms. CaMKII phosphorylatesthe gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b, gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a, gifchars/beta2.gif" BORDER=0 ALIGN="middle">3, and gifchars/beta2.gif" BORDER=0 ALIGN="middle">4 isoforms with similar initial rates and final stoichiometries of 6-12 mol of phosphateper mol of protein. However, activated/autophosphorylated CaMKII binds to gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b and gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a with a similarapparent affinity but does not bind to gifchars/beta2.gif" BORDER=0 ALIGN="middle">3 or gifchars/beta2.gif" BORDER=0 ALIGN="middle">4. Prephosphorylation of gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b and gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a by CaMKII substantiallyreduces the binding of autophosphorylated CaMKII. Residues surrounding Thr498 in gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a are highlyconserved in gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b but are different in gifchars/beta2.gif" BORDER=0 ALIGN="middle">3 and gifchars/beta2.gif" BORDER=0 ALIGN="middle">4. Site-directed mutagenesis of this domain in gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a showedthat Thr498 phosphorylation promotes dissociation of CaMKII-gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a complexes in vitro and reducesinteractions of CaMKII with gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a in cells. Mutagenesis of Leu493 to Ala substantially reduces CaMKIIbinding in vitro and in intact cells but does not interfere with gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a phosphorylation at Thr498. In combination,these data show that phosphorylation dynamically regulates the interactions of specific isoforms of theCa2+ channel gifchars/beta2.gif" BORDER=0 ALIGN="middle"> subunits with CaMKII.
gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a subunit ofvoltage-gated Ca2+ channels at Thr498 to facilitate cardiac L-type Ca2+ channels. CaMKII colocalizeswith gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a in cardiomyocytes and also binds to a domain in gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a that contains Thr498 and exhibits an aminoacid sequence similarity to the CaMKII autoinhibitory domain and to a CaMKII binding domain in theNMDA receptor NR2B subunit (Grueter, C. E. et al. (2006) Mol. Cell 23, 641). Here, we explore theselectivity of the actions of CaMKII among Ca2+ channel gifchars/beta2.gif" BORDER=0 ALIGN="middle"> subunit isoforms. CaMKII phosphorylatesthe gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b, gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a, gifchars/beta2.gif" BORDER=0 ALIGN="middle">3, and gifchars/beta2.gif" BORDER=0 ALIGN="middle">4 isoforms with similar initial rates and final stoichiometries of 6-12 mol of phosphateper mol of protein. However, activated/autophosphorylated CaMKII binds to gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b and gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a with a similarapparent affinity but does not bind to gifchars/beta2.gif" BORDER=0 ALIGN="middle">3 or gifchars/beta2.gif" BORDER=0 ALIGN="middle">4. Prephosphorylation of gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b and gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a by CaMKII substantiallyreduces the binding of autophosphorylated CaMKII. Residues surrounding Thr498 in gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a are highlyconserved in gifchars/beta2.gif" BORDER=0 ALIGN="middle">1b but are different in gifchars/beta2.gif" BORDER=0 ALIGN="middle">3 and gifchars/beta2.gif" BORDER=0 ALIGN="middle">4. Site-directed mutagenesis of this domain in gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a showedthat Thr498 phosphorylation promotes dissociation of CaMKII-gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a complexes in vitro and reducesinteractions of CaMKII with gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a in cells. Mutagenesis of Leu493 to Ala substantially reduces CaMKIIbinding in vitro and in intact cells but does not interfere with gifchars/beta2.gif" BORDER=0 ALIGN="middle">2a phosphorylation at Thr498. In combination,these data show that phosphorylation dynamically regulates the interactions of specific isoforms of theCa2+ channel gifchars/beta2.gif" BORDER=0 ALIGN="middle"> subunits with CaMKII.