Differential Proteomic Analysis Of Ubiquitinated Proteins Implicated In Breast Cancer

The ubiquitin-proteasome proteolytic pathway, a major pathway for protein degradation in cells, plays a critical role in the protein metabolism. So abnormality of the ubiquitin -proteasome proteolytic pathway is closely related to many diseases, especially cancer. In this research , by enriching ubiquitinated proteins with polyubiquitin affinity beads firstly, and then separating them with one dimentional SDS-PAGE followed by mass spectrometric identification, the differential ubiquitinated proteins between normal cell line (HBL-100) and tumor cell line (MDA-MB-231) were compared. AS a result, totals of 136 differential proteins were identified . By analyzing functions of differential proteins and referring to other related research data, it was found that the differential ubiquitinated proteins/enzymes were mainly involved in: (1)ubiquitin-proteasome proteolytic pathway. For example, Splice isoform 2 of E3 ubiquitin protein ligase URE-B1 was only identified in tumor cell; (2) cell cycle/apoptosis and transcription/translation, such as TACC1; GlutamyltransFera -se; P38-2G4; Mitotic checkpoint protein BUB3; ASH1L; (3)Cell structure formation, incluing Spectrin; Histone; (4)DNA repair. For example, RUVBL2 and DDIT4 were only identified in tumor cell line. The results of this study allow us to make further understanding of the relationship between ubiquitin-proteasome pathway and breast cancer occurrence and development , and provide a theoretical basis for diagnosing and treating breast cancer.