Thumb domains of the three epithelial Na⁺ channel subunits have distinct functions.

ABSTRACT: The epithelial Na⁺ channel (ENaC) possesses a large extracellular domain formed by a β-strand core enclosed by three peripheral α-helical subdomains, which have been dubbed thumb, finger, and knuckle. Here we asked whether the ENaC thumb domains play specific roles in channel function. To this end, we examined the characteristics of channels lacking a thumb domain in an individual ENaC subunit (α, β, or γ). Removing the γ subunit thumb domain had no effect on Na⁺ currents when expressed in Xenopus oocytes, but moderately reduced channel surface expression. In contrast, ENaCs lacking the α or β subunit thumb domain exhibited significantly reduced Na⁺ currents along with a large reduction in channel surface expression. Moreover, channels lacking an α o

SUBMITTER: Sheng S 

PROVIDER: S-EPMC6231141 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature