| Negatively charged residues in the N-terminal of the AID helix confer slow voltage dependent inactivation gating to CaV1.2. | |
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MedLine Citation:
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PMID: 15339810 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The E462R mutation in the fifth position of the AID (alpha1 subunit interaction domain) region in the I-II linker is known to significantly accelerate voltage-dependent inactivation (VDI) kinetics of the L-type CaV1.2 channel, suggesting that the AID region could participate in a hinged-lid type inactivation mechanism in these channels. The recently solved crystal structures of the AID-CaVbeta regions in L-type CaV1.1 and CaV1.2 channels have shown that in addition to E462, positions occupied by Q458, Q459, E461, K465, L468, D469, and T472 in the rabbit CaV1.2 channel could also potentially contribute to a hinged-lid type mechanism. A mutational analysis of these residues shows that Q458A, Q459A, K465N, L468R, D469A, and T472D did not significantly alter VDI gating. In contrast, mutations of the negatively charged E461, E462, and D463 to neutral or positively charged residues increased VDI gating, suggesting that the cluster of negatively charged residues in the N-terminal end of the AID helix could account for the slower VDI kinetics of CaV1.2. A mutational analysis at position 462 (R, K, A, G, D, N, Q) further confirmed that E462R yielded faster VDI kinetics at +10 mV than any other residue with E462R >> E462K approximately E462A > E462N > wild-type approximately E462Q approximately E462G > E462D (from the fastest to the slowest). E462R was also found to increase the VDI gating of the slow CEEE chimera that includes the I-II linker from CaV1.2 into a CaV2.3 background. The fast VDI kinetics of the CaV1.2 E462R and the CEEE + E462R mutants were abolished by the CaVbeta2a subunit and reinstated when using the nonpalmitoylated form of CaVbeta2a C3S + C4S (CaVbeta2a CS), confirming that CaVbeta2a and E462R modulate VDI through a common pathway, albeit in opposite directions. Altogether, these results highlight the unique role of E461, E462, and D463 in the I-II linker in the VDI gating of high-voltage activated CaV1.2 channels. |
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Authors:
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Omar Dafi; Laurent Berrou; Yolaine Dodier; Alexandra Raybaud; Rémy Sauvé; Lucie Parent |
Publication Detail:
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Type: Comparative Study; Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't Date: 2004-08-31 |
Journal Detail:
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Title: Biophysical journal Volume: 87 ISSN: 0006-3495 ISO Abbreviation: Biophys. J. Publication Date: 2004 Nov |
Date Detail:
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Created Date: 2004-10-27 Completed Date: 2005-03-25 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0370626 Medline TA: Biophys J Country: United States |
Other Details:
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Languages: eng Pagination: 3181-92 Citation Subset: IM |
Affiliation:
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Département de Physiologie, Membrane Protein Research Group, Université de Montréal, Montréal, Québec H3C 3J7, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acid Substitution Amino Acids / metabolism Animals Calcium Channels, L-Type / physiology* Cells, Cultured Ion Channel Gating / physiology* Membrane Potentials / physiology* Mutagenesis, Site-Directed Oocytes / physiology* Protein Structure, Secondary Static Electricity Structure-Activity Relationship Xenopus laevis |
| Chemical | |
Reg. No./Substance:
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0/Amino Acids; 0/Calcium Channels, L-Type; 0/L-type calcium channel alpha(1C) |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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