ABSTRACT
Objective To identify the mediators of CDC42 signaling pathway involved in hepatitis B virus X protein (HBx)-mediated cellular transformation.Methods The mass defect-based pseudo-isobaric dimethyl labeling method (pIDL)was used to detect the differentially expressed proteins with a deficiency of CDC42.Furthermore,we conducted a gene ontology (GO)of differentially expressed proteins.Results and Conclusion We totally qualified 3409 proteins and found 220 differentially expressed proteins.Palladin,formin-like 1 (FMNL1)and keratin-19,which were implicated in cytoskeleton organization,were down-regulated with the deficiency of CDC42.Our results have provided candidate genes and proteins that may play an important role in HBx-mediated cellular transformation.
ABSTRACT
Ubiquitination is one of the most major post-translational modifications playing important role in regulation of intra-cellular proteins' stability, degradation, localization and biological activity. However, these proteins are difficult to be detected due to their low abundance, short half-life. In this study, ubiquitin-binding domains (UBDs) were constructed to purify the ubiquitinated proteins from Hep3B cells. Ubiquitinated proteins and sites were detected by LC-MS/MS. A total of 1 900 potential ubiquitinated proteins were identified. Among them, 158 ubiquitinated sites were identified, belonging to 102 proteins. Bioinformatics analysis revealed that the enriched pathways of ubiquitinated proteins were closely related to tumor occurrence and development. The dysfunction of ubiquitin-proteasome has a high correlation with cell signaling and extracellular matrix changing in tumor cells.