Inactivation of L-type calcium channels is determined by the length of the N terminus of mutant beta(1) subunits.
Détails
ID Serval
serval:BIB_44AC15298CEB
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Inactivation of L-type calcium channels is determined by the length of the N terminus of mutant beta(1) subunits.
Périodique
Pflügers Archiv
ISSN
1432-2013[electronic], 0031-6768[linking]
Statut éditorial
Publié
Date de publication
2010
Volume
459
Numéro
3
Pages
399-411
Langue
anglais
Résumé
Voltage-dependent calcium channel (Ca(v)) pores are modulated by cytosolic beta subunits. Four beta-subunit genes and their splice variants offer a wide structural array for tissue- or disease-specific biophysical gating phenotypes. For instance, the length of the N terminus of beta(2) subunits has major effects on activation and inactivation rates. We tested whether a similar mechanism principally operates in a beta(1) subunit. Wild-type beta(1a) subunit (N terminus length 60 aa) and its newly generated N-terminal deletion mutants (51, 27 and 18 aa) were examined within recombinant L-type calcium channel complexes (Ca(v)1.2 and alpha(2)delta2) in HEK293 cells at the whole-cell and single-channel level. Whole-cell currents were enhanced by co-transfection of the full-length beta(1a) subunit and by all truncated constructs. Voltage dependence of steady-state activation and inactivation did not depend on N terminus length, but inactivation rate was diminished by N terminus truncation. This was confirmed at the single-channel level, using ensemble average currents. Additionally, gating properties were estimated by Markov modeling. In confirmation of the descriptive analysis, inactivation rate, but none of the other transition rates, was reduced by shortening of the beta(1a) subunit N terminus. Our study shows that the length-dependent mechanism of modulating inactivation kinetics of beta(2) calcium channel subunits can be confirmed and extended to the beta(1) calcium channel subunit.
Mots-clé
Voltage-Dependent Calcium Channel, Whole-Cell Recording, Single Channel, Modeling, Channel Gating, Gated CA2+ Channels, Sodium-Channel, Single-Channel, Hypopp-1 Mutations, CA(V)1.2 Channel, Skeletal-Muscle, Gating Currents, Splice Variants, Amino-Terminus, Human Heart
Pubmed
Web of science
Création de la notice
09/03/2010 11:55
Dernière modification de la notice
20/08/2019 13:49