Jun Yin

B.S. (1995): Peking University, Beijing, China
M.S. (1997): Rutgers University at New Brunswick
Ph.D. (2003): University of California at Berkeley
Postdoctoral Associate (2003-2006): Harvard Medical School
Assistant Professor (2006-2013): University of Chicago
Associate professor (2013-present): Georgia State University

Protein engineering, phage display, yeast cell surface display, proteomics, protein posttranslational modification, cell signaling.

Research Interest:

Protein modification by ubiquitin (UB) controls diverse cellular processes. UB is conjugated to cellular proteins by sequential transfer through an E1-E2-E3 enzymatic cascade. The cross-activities of 2 E1s, 50 E2s and hundreds of E3s encoded make it difficult to identify the cellular targets of a specific E3 to map it on a cell signaling network. To solve this problem, we used phage and yeast cell surface display to engineer orthogonal UB-E1, E1-E2 and E2-E3 pairs so that the engineered UB (xUB) can be exclusively used by a specific E3 to label its substarte proteins. We have constructed stable cell lines to express the engineered xE1-xE2-xE3 cascade for orthogonal UB transfer (OUT). We carried out tandem purification and proteomic profiling to identify the downstream targets of important E3s including E6AP, Rsp5, UBE4B, CHIP, Mdm2, Traf6, and BRCA1. We also study the mechanism of UB chain assembly by unnatural amino acid incorporation, structural biology, and enzyme mechanistic analysis.