Table of Contents
International Scholarly Research Notices
Volume 2014, Article ID 517126, 6 pages
Research Article

Nitrite as Direct S-Nitrosylating Agent of Kir2.1 Channels

Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, Arcavacata di Rende, 87036 Cosenza, Italy

Received 25 March 2014; Revised 7 May 2014; Accepted 21 May 2014; Published 16 July 2014

Academic Editor: Maythem Saeed

Copyright © 2014 Gabriella Montesanti et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Nitrite, a physiological nitric oxide (NO) storage form and an alternative way for NO generation, affects numerous biological processes through NO-dependent and independent pathways, including the S-nitrosylation of thiol-containing proteins. Mechanisms underlying these phenomena are not fully understood. The purpose of this study was to analyse in the rat heart (as prototype of mammalian heart) whether nitrite affects S-nitrosylation of cardiac proteins and the potential targets for S-nitrosylation. Rat hearts, perfused according to Langendorff, were exposed to nitrite. By Biotin Switch Method, we showed that nitrite treatment increased the degree of S-nitrosylation of a broad range of membrane proteins. Further analysis, conducted on subfractioned proteins, allowed us to identify a high level of nitrosylation in a small range of plasmalemmal proteins characterized by using an anti-Kir2.1 rabbit polyclonal antibody. We also verified that this effect of nitrite is preserved in the presence of the NO scavenger PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide). Our results suggest, for the first time, that nitrite represents a direct S-nitrosylating agent in cardiac tissues and that inward-rectifier potassium ion channels (Kir2.1) are one of the targets. These observations are of relevance since they support the growing evidence that nitrite is not only a NO reserve but also a direct modulator of important functional cardiac proteins.