Modulation of the α1A Ca2+ channel by β subunits at physiological Ca2+ concentration

FEBS Letters

Nargeot, Joel¹  Cens, Thierry¹  Mangoni, Matteo E.¹  Charnet, Pierre¹ 

[1] CRBM CNRS UPR 9008 INSERM U249, 1919 Route de Mende, BP 5051, 34033 Montpellier, France

关键词: P- and Q-type Ca2+ channels;    α1A subunit;    ωConotoxin MVII C;    Rat brain;   

DOI  :  10.1016/0014-5793(96)00704-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The class A Ca²⁺ channel αl subunit (αlA) was expressed in Xenopus oocytes alone or in combination with the βlb, β2a, β3, or β4 subunit. Analysis of voltage-dependent activation and inactivation in the presence of 1.8 mM external Ca²⁺ showed an hyperpolarising shift of both relations when compared to similar recordings performed in the presence of 40 mM Ba²⁺. These shifts, which differed for activation and inactivation, were strongly modulated by the nature of the co-expressed β subunit. On the other hand, for each combination, the kinetics of inactivation were similar in 1.8 mM Ca²⁺ and 40 mM Ba²⁺ (for example co-expression of the β2a subunit reduced inactivation using either 40 mM Ba²⁺ or 1.8 mM Ca²⁺). Thus, modulation of channel properties by the β subunit is different in physiological Ca²⁺ or high Ba²⁺ concentrations. These results must be taken into consideration to extrapolate the role of the β subunit in native cells.

【 授权许可】

Unknown