High impact information on SCNN1D

• Indirect immunofluorescence microscopy revealed that delta-ENaC is co-expressed with alpha-, beta-, and gamma-ENaC in H441 cells at the protein level [1].
• Co-immunoprecipitation of delta-ENaC with alpha- and gamma-subunits in H441 and transfected COS-7 cells suggests an interaction among these proteins [1].
• Reverse transcription-PCR revealed that delta-ENaC is co-expressed with alpha beta gamma-subunits in cultured human lung (H441 and A549), pancreatic (CFPAC), and colonic epithelial cells (Caco-2) [1].
• Although hENaCdelta homomer was also significantly activated by capsazepine, unexpectedly, capsazepine had no effect on hENaCalpha and caused a slight decrease on the hENaCalphabetagamma current [2].
• In conclusion, capsazepine acts on ENaCdelta and acts together with protons [2].

Biological context of SCNN1D

• To explain this discrepancy, we searched for novel functional properties of homomeric ENaCdelta and investigated the detailed tissue distribution in humans [3].

Anatomical context of SCNN1D

• When human ENaCdelta was expressed in Xenopus oocytes and Chinese hamster ovary cells, a reduction of extracellular pH activated this channel (half-maximal pH for an activation of 5.0), and the acid-induced current was abolished by amiloride [3].
• RNA dot-blot analyses showed that ENaCdelta mRNA was widely distributed throughout the brain and was also expressed in the heart, kidney, and pancreas in humans [3].
• Northern blotting confirmed that ENaCdelta was expressed in the cerebellum and the hippocampus [3].

Analytical, diagnostic and therapeutic context of SCNN1D

• The hypothesis that external protons may activate human delta-ENaC was addressed by expressing deltabetagamma-hENaC in Xenopus oocytes and evaluating proton-activated current with the two-electrode voltage clamp technique [4].

References