Calmodulin binding is dispensable for Rem-mediated Ca2+ channel inhibition
Calmodulin binding is dispensable for Rem-mediated Ca2+ channel inhibition
复制标题
DOI：
10.1007/s11010-007-9670-8
复制
发表时间：
2008-03-01
影响因子：
4.3
通讯作者：
Andres, Douglas A.
中科院分区：
文献类型：
--
作者：
Correll, Robert N.;Pang, Chunyan;Andres, Douglas A.
Ras相关RGK家族的GTP酶是高电压激活（HVA）Ca 2+通道活性的负调节剂。在这项研究中，我们研究了钙调素（CaM）协会在雷姆介导的钙通道抑制的作用。我们发现Rem/CaM相互作用是Ca 2+依赖性的，并且在位置277之前截断Rem C-末端防止CaM结合。将Rem C-末端在残基265和276之间连续诱变为丙氨酸产生了两种突变体（Rem（L271 A）和Rem（L274 A）），其显示出降低的CaM结合，并且这些突变体的子集显示出比Rem（WT）显著更低的细胞外周定位。然而，减少钙调素协会或膜运输并不影响功能，因为所有的雷姆突变体可以完全抑制Ca 2+通道。Rem 1 -275截短突变体部分抑制Ca 2+通道活性，尽管它不能结合钙调素。两者合计，这些研究表明，钙调素协会是不是必不可少的，无论是雷姆介导的钙通道抑制或质膜定位。
GTPases of the Ras-related RGK family are negative regulators of high voltage-activated (HVA) Ca2+ channel activity. In this study, we examined the role of calmodulin (CaM) association in Rem-mediated Ca2+ channel inhibition. We found that the Rem/CaM interaction is Ca2+-dependent, and that truncation of the Rem C-terminus before position 277 prevents CaM binding. Serial mutagenesis of the Rem C-terminus between residues 265 and 276 to alanine generated two mutants (Rem(L271A) and Rem(L274A)) that displayed reduced CaM binding, and a subset of these mutants displayed significantly lower cell periphery localization than Rem(WT). However, reductions in CaM association or membrane trafficking did not affect function, as all Rem mutants could completely inhibit Ca2+ channels. The Rem1-275 truncation mutant partially inhibited Ca2+ channel activity despite its inability to bind CaM. Taken together, these studies indicate that CaM association is not essential for either Rem-mediated Ca2+ channel inhibition or plasma membrane localization.