Properties of Calmodulin Binding to NaV1.2 IQ Motif and Its Autism-Associated Mutation R1902C
Properties of Calmodulin Binding to NaV1.2 IQ Motif and Its Autism-Associated Mutation R1902C
复制标题
钙调蛋白与 NaV1.2 IQ 基序结合的特性及其与自闭症相关的突变 R1902C
DOI：
10.1007/s11064-020-03189-7
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发表时间：
2021-01-04
影响因子：
4.4
通讯作者：
Guo, Feng
中科院分区：
文献类型：
--
作者：
Jia, Wanying;Liu, Junyan;Guo, Feng
电压门控钠通道（VGSC）是可兴奋细胞动作电位启动和传播的基础。Ca 2 +/钙调蛋白（CaM）结合VGSC II型（NaV1.2）异亮氨酸和谷氨酰胺（IQ）基序。据报道，与野生型IQ基序相比，NaV1.2 IQ基序中的自闭症相关突变Arg 1902 Cys（R1902 C）影响了CaM和IQ基序之间的结合。然而，Ca 2+调节的CaM与NaV1.2 IQ（1901 Lys-1927 Lys，IQwt）和突变IQ基序（IQR 1902 C）结合的详细性质仍不清楚。在这里，钙调素和钙调素的组成蛋白，包括N-和C叶的结合能力的IQ模体的NaV1.2及其突变体的蛋白质下拉实验进行了研究。我们发现CaM和IQ基序之间的结合是U形的，其中在[Ca 2 +]浓度为100 nM时最高，在[Ca 2 +]浓度为100 nM时最低。在IQR 1902 C突变体中，CaM结合的Ca 2+依赖性几乎丧失。因此，与IQwt相比，CaM与IQR 1902 Cat 100和500 nM [Ca 2 +]的结合增加。CaM的N端和C端均能与NaV1.2IQ模体和IQR 1902 C突变体结合，但C端的作用最大。此外，CaMKII对CaM和NaV1.2 IQ基序之间的结合没有影响。本研究为CaM调控NaV1.2 IQwt和IQR 1902 Cmotif（孤独症相关突变）提供了新的视角。
Voltage-gated sodium channels (VGSCs) are fundamental to the initiation and propagation of action potentials in excitable cells. Ca2+/calmodulin (CaM) binds to VGSC type II (NaV1.2) isoleucine and glutamine (IQ) motif. An autism-associated mutation in NaV1.2 IQ motif, Arg1902Cys (R1902C), has been reported to affect the combination between CaM and the IQ motif compared to that of the wild type IQ motif. However, the detailed properties for the Ca2+-regulated binding of CaM to NaV1.2 IQ (1901Lys-1927Lys, IQwt) and mutant IQ motif (IQR1902C) remains unclear. Here, the binding ability of CaM and CaM's constituent proteins including N- and C lobe to the IQ motif of NaV1.2 and its mutant was investigated by protein pull-down experiments. We discovered that the combination between CaM and the IQ motif was U-shaped with the highest at [Ca2+] ≈ free and the lowest at 100 nM [Ca2+]. In the IQR1902Cmutant, Ca2+-dependence of CaM binding was nearly lost. Consequently, the binding of CaM to IQR1902Cat 100 and 500 nM [Ca2+] was increased compared to that of IQwt. Both N- and C lobe of CaM could bind with NaV1.2 IQ motif and IQR1902Cmutant, with the major effect of C lobe. Furthermore, CaMKII had no impact on the binding between CaM and NaV1.2 IQ motif. This research offers novel insight to the regulation of NaV1.2 IQwtand IQR1902Cmotif, an autism-associated mutation, by CaM.