Dr. Ziyin Li
The University of Texas Health Science Center at Houston
McGovern Medical School
Department of Microbiology and Molecular Genetics
My laboratory is mainly interested in understanding the molecular mechanism of mitosis and cytokinesis. We use Trypanosoma brucei, a unicellular eukaryote and the causative agent of human sleeping sickness, as a model to address the fundamental questions of how mitosis and cytokinesis are regulated and coordinated during cell division. The current focus is on the cell cycle regulatory pathways consisting of protein kinases such as Aurora B kinase, Polo-like kinase, and Tousled-like kinase, and spindle-associated motor proteins. Moreover, we are also interested in the role of ubiquitin-dependent and -independent proteolysis in various cell biological processes. ATP-dependent protease complexes are present in all three kingdoms of life where they ride the cell of mis-folded or damaged proteins and control the level of certain regulatory proteins. These proteases include the 26S proteasome in eukaryotes, Archaea, and Actinomycetales and the HslVU protease in eubacteria. The current focus is on three proteolytic pathways: the Cullin-RING ubiquitin ligase (CRL) and the anaphase-promoting complex/ cyclosome (APC/C) on cell cycle control and HslVU protease on mitochondrial DNA replication. We use a combination of genetics, biochemistry, cell biology, molecular biology, and proteomics to elucidate the molecular and cellular basis of cell division in trypanosomes, which hopefully could provide excellent drug targets for chemotherapy.
A tutorial in my laboratory would expose a student to a wide variety of molecular biological, genetic, biochemical, and cell biological techniques. For example, gene cloning and targeting, RNA interference, gene knockout and knock-in, Western blot, co-immunoprecipitation, tandem affinity protein purification, protein kinase assay, purification of recombinant proteins, immunofluorescence microscopy, and electron microscopy.