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KMID : 0578320100300030185
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Molecules and Cells
2010 Volume.30 No. 3 p.185 ~ p.191
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Interaction of T-Type Calcium Channel CaV3.3 with the β-Subunit
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Bae Jin-Hee
Suh Eui-Jin
Lee Cheol-ju
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Abstract
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The β-subunit of high-voltage-activated (HVA) calcium channels is essential for the regulation of expression and gating. On the other hand, various reports have suggested that β subunits play no role in the regulation of low-voltage-activated T-type channels. In addition there has been no clear demonstration of a physical interaction between the β-subunit of T-type channel with β-subunit. In this study, we systematically investigated the interaction between CaVα and CaVβ. The four CaVβ isoforms were expressed in a bacterial system and purified into homogeneity, whereas the ten types of CaVα alpha interaction domain (AID) peptides were chemically synthesized. All possible combinations of CaVα and CaVβ were then tested for by in vitro immunoassays. We describe here the identification of a new interaction between CaV3.3 and CaVβ proteins. This interaction is of low affinity compared to that between the AID of the HVA β-subunit and the alpha-binding pocket (ABP) site of the β-subunit. The AID peptide of HVA channel exerted no effect on the CaV3.3-CaVβ interaction, thus demonstrating that another site not in the ABP of CaVβ protein played a role in binding with CaV3.3. This is the first demonstration of an α-β subunit interaction in a T-type calcium channel.
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KEYWORD
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calcium channel, CaV3.3, β subunit
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