Ubiquitination-activating enzymes UBE1 and UBA6 regulate ubiquitination and expression of cardiac sodium channel Nav1.5.

Ubiquitination-activating enzymes UBE1 and UBA6 regulate ubiquitination and expression of cardiac sodium channel Nav1.5. Biochem J. 2020 Apr 21;: Authors: Hu Y, Bai X, Zhang C, Chakrabarti S, Tang B, Xiong H, Wang Z, Yu G, Xu C, Chen Q, Wang QK Abstract Cardiac sodium channel Nav1.5 is associated with cardiac arrhythmias and heart failure. Protein ubiquitination is catalyzed by an E1-E2-E3 cascade of enzymes. However, the E1 enzyme catalyzing Nav1.5 ubiquitination is unknown. Here, we show that UBE1 and UBA6 are two E1 enzymes regulating Nav1.5 ubiquitination and expression. Western blot analysis and patch-clamping recordings showed that overexpression of UBE1 or UBA6 increased ubiquitination of Nav1.5 and significantly reduced Nav1.5 expression and sodium current density, and knockdown of UBE1 or UBA6 expression significantly increased Nav1.5 expression and sodium current density in HEK293/Nav1.5 cells. Similar results were obtained in neonatal cardiomyocytes. Bioinformatic analysis predicted two ubiquitination sites at K590 and K591. Mutations of K590 and K591 to K590A and K591A abolished the effects of overexpression or knockdown of UBE1 or UBA6 on Nav1.5 expression and sodium current density. Western blot analysis showed that the effects of UBE1 or UBA6 overexpression on the ubiquitination and expression of Nav1.5 were abolished by knockdown of UBC9, a putative E2 enzyme reported for Nav1.5 ubiquitination by us. Interestingly, re...
Source: The Biochemical Journal - Category: Biochemistry Authors: Tags: Biochem J Source Type: research