The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels contain multiple S-palmitoylation sites
The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels contain multiple S-palmitoylation sites
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DOI：
10.1007/s12576-015-0420-5
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发表时间：
2016-05-01
影响因子：
2.3
通讯作者：
Takano, Makoto
中科院分区：
文献类型：
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作者：
Itoh, Masayuki;Ishihara, Keiko;Takano, Makoto
超极化激活的环核苷酸门控通道(HCN1-4)在神经元远端树突上的表达被认为是为了改变中枢神经系统中突触的整合。然而，枝晶局部化的机制还不完全清楚。最近的研究表明，S-棕榈酰化在突触后膜上各种分子的丰富中起着重要作用。因此，我们进行了酰基-生物素交换实验，发现在HEK293细胞中，HCN_1、HCN_2和HCN_4是S棕榈酰化的，而不是HCN_3。细胞内多个半胱氨酸残基的N末端突变是完全抑制S棕榈酰化所必需的。然而，当在HEK293细胞或非洲爪哇卵母细胞中表达时，这种突变对HCN_2蛋白的表面表达或HCN_2电流的电生理性质影响很小。这些发现为深入了解S棕榈酰化HCN通道在天然神经元中的生理作用提供了依据。
Expression of hyperpolarization-activated cyclic nucleotide-gated channels (HCN1-4) on distal dendrites of neurons is suggested to modify synaptic integration in the central nervous system. However, the mechanisms of dendritic localization are not fully understood. Recent studies have revealed that S-palmitoylation plays an important role in the enrichment of various molecules at the postsynaptic membrane. Thus, we performed an acyl-biotinyl exchange assay, and found that HCN1, HCN2, and HCN4, but not HCN3, were S-palmitoylated in HEK293 cells. Mutation of multiple intracellular cysteine residues at the N-terminus of HCN2 was required for complete inhibition of S-palmitoylation. However, this mutagenesis had a minimal effect on surface expression of HCN2 proteins or electrophysiological properties of HCN2 current when expressed in HEK293 cells or in Xenopus oocytes. These findings provide insight into the physiological roles of S-palmitoylation of HCN channels in native neurons.