Xiang-Dong Zhang, Ph.D.

Research Interests

As a cell biologist I am interested in studying two important cellular processes, cell-cycle control and nucleocytoplasmic transport.  My research is particularly focused on understanding the role of sumoylation, an essential post-translational protein modification, in regulation of these two processes in eukaryotic cells.  Sumoylation is characterized by covalent attachment of small ubiquitin-related modifier protein (SUMO) to hundreds of different proteins, and thereby alters these target proteins’ activity, localization, stability, and/or interaction with other proteins.  SUMO modification has emerged as a general mechanism in regulation of a wide range of cellular processes, including cell division, DNA repair, gene expression, protein trafficking, stress response, and ubiquitin-dependent proteolysis.  Consistent with its diverse roles in cells, SUMO modification is associated with many diseases, including cancer, diabetes, brain ischemia, cardiovascular diseases, and neurodegenerative diseases. 

Current research projects

1. Elucidate the role of SUMO-2/3 modification at centromeres and kinetochores in regulation of cell cycle progression through mitosis.  Mammals express three SUMO isoforms: SUMO-1 and the closely related SUMO-2 and SUMO-3 (referred to as SUMO-2/3). SUMO-2/3 modified proteins localize to centromeres and kinetochores during prophase and metaphase, while SUMO-1 modified proteins associate with the mitotic spindle.
    
2. Investigate the role of SUMO-1-modified RanGAP1, a key regulator of nucleocytoplasmic transport, at annulate lamellae.  As cytoplasmic organelles with largely unknown function, annulate lamellae are associated with endoplasmic reticulum and also embedded with pore complexes, which are morphologically similar to nuclear pore complexes.

Teaching

Bio 111 - Introduction to Biology

Bio 214 - Introduction to Cell Biology