Derlinl Regulation Of Ubiquitin-mediated Epithelial Sodium Channel(ENaC) Degradation

In recent years,Hypertension is one of the major health diseases that endanger human health.According to the research,by the end of 2013,more than 200 million patients had been diagnosed with hypertension in China,and the growth rate had reached 10 million per year.Essential hypertension is a chronic disease caused by the interaction of genetic and environmental factors.In many cases,high salt,hormonal disorders and other environmental factors play a role in the body by different cell membrane proteins.Epithelial sodium channel(ENaC)is one of the important membrane proteins.More studies show that refractory hypertension found in clinic,including salt-sensitive hypertension,relates to excessive activation of ENaC.ENaC,a heteromeric channel composed of three similar but distinct subunits,α,β and γ.The channel is typically located at the apical membrane of epithelial tissues throughout the body,including the colon,the sweat glands,the salivary duct and the airway.In the kidney,ENaC is mainly distributed in the distal convoluted tubule and collecting duct of distal nephron,having a role of rate-limiting in sodium reabsorption through mediating membrane transport of Na+.Derlinl,the degradation in endoplasmic reticulum protein 1,is a moderator of E3 ubiquitin ligase.It mainly locates in the cytoplasm.We mainly research whether Derlin 1,endoplasmic reticulum-associated protein degradation 1,relates with the degradation of epithelial sodium channel(ENaC)via ubiquitination in this subject.In this subject,we found Derlin 1 could affect the expression of ENaC in the protein level,but there were no significant changes in the expression of α,β,γENaC mRNA in the presence of Derlin1.It demonstrated that Derlin1 influenced α,β,γsubunits of ENaC expression at post-translational level.And Derlinl have direct interaction with ENaC through co-immunoprecipitation(COIP)in the middle of Derlinl.Further we found that after adding MG 132,a protease inhibitor,the expression of αENaC was increased that indicated aENaC had ubiquitin proteasome degradation and Derlinl may promot degradation of ENaC via ubiquitination.Then we further found that Derlinl promoted degradation of ENaC via ubiquitination at K11-linked manner.At the same time,we found another E3 ubiquitin ligase,HUWE1,possible participates in Derlinl regulation of ubiquitin-mediated ENaC degradation by MS.This study explores the molecular mechanism of ENaC degradation in-depth,playing much theoretical and significance role of looking for the clinical prevention and treatment of primary or secondary targets for salt-sensitive hypertension.