Caβ 亚基对 Ca1.2 钙通道正向和反向转运的依赖性。

Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.

Mol Brain. 2022 May 9;15(1):43. doi: 10.1186/s13041-022-00930-x.

Auxiliary Caβ subunits interact with the pore forming Caα subunit to promote the plasma membrane expression of high voltage-activated calcium channels and to modulate the biophysical properties of Ca currents. However, the effect of Caβ subunits on channel trafficking to and from the plasma membrane is still controversial. Here, we have investigated the impact of Caβ1b and Caβ2a subunits on plasma membrane trafficking of Ca1.2 using a live-labeling strategy. We show that the Caβ1b subunit is more potent in increasing Ca1.2 expression at the plasma membrane than the Caβ2a subunit and that this effect is not related to modification of intracellular trafficking of the channel (i.e. neither forward trafficking, nor recycling, nor endocytosis). We conclude that the differential effect of Caβ subunit subtypes on Ca1.2 surface expression is likely due to their differential ability to protect Ca1.2 from degradation.

辅助 Caβ 亚基与形成孔的 Caα 亚基相互作用，促进高电压激活钙通道在质膜上的表达，并调节钙电流的生物物理特性。然而，Caβ 亚基对通道在质膜内外运输的影响仍存在争议。在这里，我们使用活细胞标记策略研究了 Caβ1b 和 Caβ2a 亚基对 Ca1.2 质膜运输的影响。我们表明，Caβ1b 亚基比 Caβ2a 亚基更有效地增加 Ca1.2 在质膜上的表达，并且这种作用与通道细胞内运输的修饰无关（即正向运输、回收或内吞作用都不受影响）。我们得出结论，Caβ 亚基亚型对 Ca1.2 表面表达的不同影响可能是由于它们对 Ca1.2 降解的保护能力不同。