Ion Channels Controlling Resting Membrane Potential of Nociceptive DRG Neuron Somata

Abstract

NCX1 protein were identified by overlay assays. In order to investigate the specific function of M369 cleavage and avoid auxiliary and indirect functions of calpain, we utilized the protease Tobacco Etch Virus (TEV) to investigate site-specific cleavage. The TEV protease recognition site was inserted at the location of M369 in NCX1. By employing the patch clamp technique on transfected HEK cells, we observed a significant reduction of NCX1 current following TEV cleavage. In conclusion, we have identified and investigated the functional role of the calpain cleavage site at M369 in the CLD of NCX1. Our findings show that cleavage of the NCX1 at M369 reduces the total current. This reduction of NCX1 activity could potentially function to compensate for altered Ca 2þ homeostasis associated with NCX upregulation during heart failure.