Ph.D., University of Texas, 1996
Areas of InterestMolecular Oncology and Human Genetics
The focus of our research is to understand the molecular mechanisms underlying protein degradation mediated by the ubiquitin-proteasome system (UPS). UPS is the primary intracellular machine responsible for elimination of abnormal proteins and selective destruction of regulatory proteins involved in a wide range of cellular processes including cell cycle control, DNA transcription, replication and repair, and stress response. Dys-regulation of UPS is implicated in various human diseases including cancers. Moreover, UPS has now become an important target for anti-cancer therapy. We use both Saccharomyces cerevisiae and mammalian systems to define the pathways that control the degradation of several key regulatory proteins. In addition, we are studying the differential response of normal cells and cancer cells to the inhibitors of UPS.
Wang, L., Mao, X., Ju, D. & Xie, Y. Rpn4 is a physiological substrate of the Ubr2 ubiquitin ligase. J. Biol. Chem. 279, 55218-55223, 2004.
Ju, D. & Xie, Y. Proteasomal degradation of RPN4 via two distinct mechanisms: ubiquitin-dependent and -independent. J. Biol. Chem. 279, 23851-23854, 2004.
Ju, D. & Xie, Y. Identification of the preferential ubiquitination site and ubiquitin- dependent degradation signal of Rpn4. J. Biol. Chem. 281, 10657-10662, 2006.
Ju, D., Wang, X., Xu, H. & Xie, Y. The armadillo repeats of the Ufd4 ubiquitin ligase recognize ubiquitin-fusion proteins. FEBS Lett 581, 265-270, 2007.
Xu, H., Ju, D., Jarois, T. & Xie, Y. Diminished feedback regulation of proteasome expression and resistance to proteasome inhibitors in breast cancer cells. Breast Cancer Res Treat [Epub ahead of print: DOI 10.1007/s10549-007-9553-4], 2007.
Ju, D., Wang, X., Xu, H. and Xie, Y. Genome-wide analysis identifies MYND-domain protein Mub1 as an essential factor for Rpn4 ubiquitylation. Mol. Cell. Biol. [published ahead of print on 10 December 2007, doi:10.1128/MCB.01787-07, 2007.