Dataset Information

Epithelial Na+ Channel (ENaC) Formed by One or Two Subunits Forms Functional Channels That Respond to Shear Force.

ABSTRACT: Canonical epithelial sodium channels (ENaCs) are heterotrimers formed by ?, ?, and ? ENaC subunits in vertebrates and belong to the Degenerin/ENaC family of proteins. Proteins from this family form mechanosensitive channels throughout the animal kingdom. Activity of canonical ENaC is regulated by shear force (SF) mediating Na+ absorption in the kidney and vascular tone of arteries. Expression analysis suggests that non-canonical ENaC, formed by single or only two subunits, exist in certain tissues, but it is unknown if these channels respond to SF. ?, ?, ?, and ? ENaC subunits were expressed either alone or in combinations of two subunits in Xenopus oocytes. Amiloride-sensitive currents and the responses to SF were assessed using two-electrode voltage clamp recordings. With the exception of ? ENaC, all homomeric channels provided amiloride-sensitive currents and responded to SF applied via a fluid stream directed onto the oocytes. Channels containing two subunits were also activated by SF. Here, the presence of the ? ENaC subunit when co-expressed with ? or ? augmented the SF response in comparison to the ???/??? ENaC. Overall, we provide evidence that non-canonical ENaC can form channels that respond to SF. This supports a potential function of non-canonical ENaC as mechanosensors in epithelial, vascular, and sensory cells.

SUBMITTER: Baldin JP

PROVIDER: S-EPMC7090232 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Epithelial Na<sup>+</sup> Channel (ENaC) Formed by One or Two Subunits Forms Functional Channels That Respond to Shear Force.

Baldin Jan-Peter JP Barth Daniel D Fronius Martin M

Frontiers in physiology 20200317

Canonical epithelial sodium channels (ENaCs) are heterotrimers formed by α, β, and γ ENaC subunits in vertebrates and belong to the Degenerin/ENaC family of proteins. Proteins from this family form mechanosensitive channels throughout the animal kingdom. Activity of canonical ENaC is regulated by shear force (SF) mediating Na<sup>+</sup> absorption in the kidney and vascular tone of arteries. Expression analysis suggests that non-canonical ENaC, formed by single or only two subunits, exist in ce ...[more]

PMID: 32256376

Similar Datasets

Project description:BACKGROUND: In rodents, dietary Na+ deprivation reduces gustatory responses of primary taste fibers and central taste neurons to lingual Na+ stimulation. However, in the rat taste bud cells Na+ deprivation increases the number of amiloride sensitive epithelial Na+ channels (ENaC), which are considered as the "receptor" of the Na+ component of salt taste. To explore the mechanisms, the expression of the three ENaC subunits (alpha, beta and gamma) in taste buds were observed from rats fed with diets containing either 0.03% (Na+ deprivation) or 1% (control) NaCl for 15 days, by using in situ hybridization and real-time quantitative RT-PCR (qRT-PCR). Since BDNF/TrkB signaling is involved in the neural innervation of taste buds, the effects of Na+ deprivation on BDNF and its receptor TrkB expression in the rat taste buds were also examined. RESULTS: In situ hybridization analysis showed that all three ENaC subunit mRNAs were found in the rat fungiform taste buds and lingual epithelia, but in the vallate and foliate taste buds, only alpha ENaC mRNA was easily detected, while beta and gamma ENaC mRNAs were much less than those in the fungiform taste buds. Between control and low Na+ fed animals, the numbers of taste bud cells expressing alpha, beta and gamma ENaC subunits were not significantly different in the fungiform, vallate and foliate taste buds, respectively. Similarly, qRT-PCR also indicated that Na+ deprivation had no effect on any ENaC subunit expression in the three types of taste buds. However, Na+ deprivation reduced BDNF mRNA expression by 50% in the fungiform taste buds, but not in the vallate and foliate taste buds. The expression of TrkB was not different between control and Na+ deprived rats, irrespective of the taste papillae type. CONCLUSION: The findings demonstrate that dietary Na+ deprivation does not change ENaC mRNA expression in rat taste buds, but reduces BDNF mRNA expression in the fungiform taste buds. Given the roles of BDNF in survival of cells and target innervation, our results suggest that dietary Na+ deprivation might lead to a loss of gustatory innervation in the mouse fungiform taste buds.

Dataset Information

Epithelial Na+ Channel (ENaC) Formed by One or Two Subunits Forms Functional Channels That Respond to Shear Force.

Publications

Epithelial Na<sup>+</sup> Channel (ENaC) Formed by One or Two Subunits Forms Functional Channels That Respond to Shear Force.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets