Proteomic Analysis Of Ubiquitinated Proteins In Colorectal Cancer Tissues

Protein ubiquitination modification plays an important role in the occurrence, development and metastasis of colorectal cancer. In this work, the total protein extracted from colorectal cancer tissues was hydrolyzed by trypsin to obtain a peptide mixture. Then the peptide mixture containing-GG tag was enriched and purified by immunoprecipitation technique. Finally, the enriched peptides were analyzed by liquid chromatography-mass spectrometry ( LC-MS) and the proteins were identified by database search. The results showed that 2036 peptides belonging to 328 proteins were identified in colorectal cancer tissues. Among them, 1497 were the modified peptides containing-GG tag, which were derived from 287 proteins. Apart from most of the peptides containing one-GG tag, 31 peptides containing two-GG tags and 3 peptides containing three-GG tags were identified. Among the identified ubiquitinated proteins, many proteins were found to be closely associated with colorectal cancer, including Prothymosin alpha, Transforming acidic coiled-coil-containing protein 3, Neutral amino acid transporter B ( 0 ). Bioinformatics analysis of the identified ubiquitinated proteins showed that ubiquitinated proteins in colorectal cancer tissues were enriched in a variety of basic biological processes and molecular functions, and were distributed in various subcellular organelles and extracellular matrix components. This study provided a specific and effective method for studying the types and distribution of ubiquitinated proteins in colorectal cancer tissues. The results could be used as primary data for further studying the molecular mechanism of ubiquitination regulation in colorectal cancer.