Sorcin modulates cardiac L-type Ca2+ current by functional interaction with the alpha(1C) subunit in rabbits

Fowler, M.R., Colotti, G., Chiancone, E., Smith, G.L. and Fearon, I.M. (2008) Sorcin modulates cardiac L-type Ca2+ current by functional interaction with the alpha(1C) subunit in rabbits. Experimental Physiology, 93(12), pp. 1233-1238. (doi:10.1113/expphysiol.2008.043497)

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Publisher's URL: http://dx.doi.org/10.1113/expphysiol.2008.043497

Abstract

We examined the modulation of the cardiac L-type Ca<sup>2+</sup> channel (LTCC) by the regulatory protein sorcin and tested the hypothesis that modulation occurred by direct interaction. Whole-cell patch-clamp recordings were made on native rabbit ventricular myocytes and HEK 293 cells expressing cardiac alpha(1C) subunits. In ventricular cells, sorcin increased peak current when using either Ca<sup>2+</sup> or Ba<sup>2+</sup> as charge carriers. In HEK 293 cells, sorcin increased peak current density when using Ba<sup>2+</sup> as a charge carrier but not when using Ca<sup>2+</sup>. In ventricular myocytes, current inactivation (tau(fast), in ms) was slowed by sorcin with Ca<sup>2+</sup> as the charge carrier, whilst in the presence of Ba2+ it was enhanced. In HEK 293 cells, sorcin significantly enhanced tau(fast), but no significant change was observed with Ba<sup>2+</sup>. This trend was mimicked by the truncated peptide, sorcin Ca<sup>2+</sup>-binding domain, which lacks the N-terminal domain. These data suggest that sorcin interacts with LTCC via its C-terminal domain, which alters current magnitude and tau(fast). These effects appear to be influenced by the prevailing experimental conditions

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Smith, Professor Godfrey and Fowler, Dr Mark
Authors: Fowler, M.R., Colotti, G., Chiancone, E., Smith, G.L., and Fearon, I.M.
Subjects:Q Science > QP Physiology
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
College of Medical Veterinary and Life Sciences
Journal Name:Experimental Physiology
ISSN:0958-0670

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