Smurf1 Regulates Its Protein Stability By Inhibiting Polyubiquitylation Of LKB1

ObjectiveExploring the upstream regulatory molecule of Liver kinase B1(LKB1)to investigate its effect on LKB1.MethodsFirstly,the Ubi Browser database was used to search for possible upstream regulatory molecules of LKB1,according to the scores,we screen out the Smurf1 gene that may regulate LKB1.Then,Smurf1 overexpression plasmid was constructed and transfected into HEK293 cells,and the expression situation of LKB1 protein was detected by western blotting.Finally,the molecular mechanism of Smurf1 up-regulating LKB1 was explored by q PCR and Co-IP.ResultsThe overexpression plasmids of p CMV5-LKB1 and p CMV5-Smurf1 were successfully constructed.The overexpression of Smurf1 protein in HEK293 cells significantly up-regulated the expression of LKB1 protein.The E3 ubiquitin ligase Smurf1 did not affect LKB1 gene transcription,but up-regulated LKB1 expression through binding to LKB1 and inhibiting its polyubiquitination degradation.ConclusionThese results indicate that Smurf1 is involved in the regulation of its protein stability by decreasing the ubiquitination of LKB1.