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)

Abstract

We examined the modulation of the cardiac L-type Ca²⁺ 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 Ca²⁺ or Ba²⁺ as charge carriers. In HEK 293 cells, sorcin increased peak current density when using Ba²⁺ as a charge carrier but not when using Ca²⁺. In ventricular myocytes, current inactivation (tau(fast), in ms) was slowed by sorcin with Ca²⁺ 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 Ba²⁺. This trend was mimicked by the truncated peptide, sorcin Ca²⁺-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 > School of Cardiovascular & Metabolic Health; College of Medical Veterinary and Life Sciences
• Journal Name: Experimental Physiology
• ISSN: 0958-0670