In:
The Journal of Biochemistry, Oxford University Press (OUP), Vol. 170, No. 5 ( 2021-12-28), p. 577-585
Kurzfassung:
Transmembrane protein 168 (TMEM168) was found to be localized on the nuclear membrane. A heterozygous mutation (c.1616G & gt;A, p. R539Q) in TMEM168 was identified in patients with Brugada syndrome. This mutation reduced expression of cardiomyocyte sodium channel Nav1.5 via Nedd4-2 E3 ubiquitin ligase-induced ubiquitination and degradation. However, the detailed molecular mechanism provoked by the TMEM168 mutant remains unclear. Here, we demonstrated that small heat shock protein αB-crystallin, which can bind to Nav1.5 and Nedd4-2 and interfere with the association of both proteins, was strongly recruited from the cell surface to the perinuclear region because of the much higher affinity of αB-crystallin with the TMEM168 mutant than with wild-type TMEM168. Following knockdown of αB-crystallin in HL-1 cardiomyocytes, the interaction of Nav1.5 with Nedd4-2 was increased, despite the reduced expression of Nav1.5. Moreover, reduction of Nav1.5 expression by αB-crystallin knockdown was rescued in the presence of a proteasome inhibitor MG-132, suggesting the importance of the αB-crystallin-modulated ubiquitin–proteasome system for the stability of Nav1.5 expression. Collectively, the balance of molecular interactions among Nav1.5, Nedd4-2 and αB-crystallin plays a role in the regulation of cardiomyocyte cell surface expression of Nav1.5, and the TMEM168 mutant disturbs this balance, resulting in a decrease in Nav1.5 expression.
Materialart:
Online-Ressource
ISSN:
0021-924X
,
1756-2651
Sprache:
Englisch
Verlag:
Oxford University Press (OUP)
Publikationsdatum:
2021
ZDB Id:
2009977-0
