Asparagine-linked glycosylation modifies voltage-dependent gating properties of CaV3.1-T-type Ca2+ channel
Asparagine-linked glycosylation modifies voltage-dependent gating properties of CaV3.1-T-type Ca2+ channel
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DOI：
10.1007/s12576-018-0650-4
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发表时间：
2019-03-01
影响因子：
2.3
通讯作者：
Ono, Katsushige
中科院分区：
文献类型：
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作者：
Liu, Yangong;Wang, Pu;Ono, Katsushige
T型通道是低电压激活的通道，在心血管系统中起作用，特别是对于起搏器活动。糖基化是蛋白质翻译后最常见的修饰之一。在各种糖基化类型中，最常见的一种是天冬酰胺连接的（N-连接的）糖基化。本研究的目的是阐明N-连接糖基化对Ca（V）3.1-T-型Ca 2+通道门控特性的作用。N-糖基化合成抑制剂衣霉素作用12 h或更长时间可引起Ca（V）3.1-T型钙通道电流（Ca（V）3.1-I-Ca.T）降低。衣霉素（24小时）显着移动激活曲线的去极化电位，而稳态失活曲线不受影响。衣霉素可加速Ca（V）3.1-I-Ca.T的钙依赖性失活，并延长失活后的恢复时间（24 h）。Ca（V）3.1-I-Ca.T在质膜上表达时对糖苷酶PNGase F不敏感。这些发现表明，N-糖基化不仅有助于Ca（V）3.1-T型Ca 2+通道的细胞表面表达，而且当通道蛋白在细胞中折叠和运输步骤期间被加工时，还有助于调节通道的门控特性。
T-type channels are low-voltage-activated channels that play a role in the cardiovascular system particularly for pacemaker activity. Glycosylation is one of the most prevalent post-translational modifications in protein. Among various glycosylation types, the most common one is asparagine-linked (N-linked) glycosylation. The aim of this study was to elucidate the roles of N-linked glycosylation for the gating properties of the Ca(V)3.1-T-type Ca2+ channel. N-linked glycosylation synthesis inhibitor tunicamycin causes a reduction of Ca(V)3.1-T-type Ca2+ channel current (Ca(V)3.1-I-Ca.T) when applied for 12h or longer. Tunicamycin (24h) significantly shifted the activation curve to the depolarization potentials, whereas the steady-state inactivation curve was unaffected. Use-dependent inactivation of Ca(V)3.1-I-Ca.T was accelerated, and recovery from inactivation was prolonged by tunicamycin (24h). Ca(V)3.1-I-Ca.T was insensitive to a glycosidase PNGase F when the channels were expressed on the plasma membrane. These findings suggest that N-glycosylation contributes not only to the cell surface expression of the Ca(V)3.1-T-type Ca2+ channel but to the regulation of the gating properties of the channel when the channel proteins were processed during the folding and trafficking steps in the cell.