Research Chemical approaches to explore the phosphoinositides related cellular process: Development of fluorogenic, fluorescent and photoaffinity labeling probes Development of small-molecule inhibitors for phosphoinositides metabolic enzymes
Qisheng Zhang Laboratory
Our lab studies lipid signaling pathways that are involved in development and diseases by developing novel chemical probes and technologies. As key components of cellular membranes, lipids also serve as signaling molecules and modify functions of proteins through either covalent or non-covalent interactions. Aberrant regulation of lipid signaling has been correlated with various diseases including cancer, diabetes, and neurodegenerative diseases. Consequently, many lipid-related proteins or processes have been used as therapeutic targets. However, lipids are dynamically metabolized and transported, making it difficult to illustrate their roles in development and diseases with limited availability of probes and technologies for lipid studies. Our research will provide novel probes, assays, and technologies to address these issues. The active projects in the lab include: 1) develop novel technologies to synthesize complex lipids, particularly phosphatidylinositides, and identify their interacting proteins in live cells; 2) develop new small molecule sensors and inhibitors for lipid metabolic enzymes such as PI3K and PLC; and 3) investigate cellular functions of lipids in different processes, particularly those regulated by small GTPases.
Our lab is interested in identifying functional small molecules from synthetic and endogenous chemical libraries and studying how these molecules regulate disease-related cell signaling. Other than traditional methods in chemical synthesis, molecular and cell biology and the emerging technique of high throughput screening, we also develop new techniques of tag-based biosynthesis and enzyme profiling, as well as small molecule array, to facilitate research. Currently, we are working on the following three projects:
Phosphatidylinositides (PIs) are a family of anchoring lipids with different combinations of phosphate groups around the inositol ring. Due to their functions of membrane recruitment and activation of downstream effector proteins, PIs are among the most versatile endogenous regulatory small molecules. Dys-regulation of PI signaling has been implicated in diseases such as Low syndrome, cancer, and myotubular myopathy. We are generating an array of natural and unnatural PIs to systematically identify PI-interacting proteins for novel drug target discovery and disease diagnosis. To facilitate these processes, we are developing new technologies of tag-based enzymatic synthesis and target identification as well as small molecule arrays.
To understand the details on how PIs are regulated in living cells, we have developed fluorescence-based reporters for PI-metabolic enzymes PLC and PI3K. These reporters are then used to monitor PLC and PI3K activity in the cells, and further utilized in high throughput screen to identify small molecule inhibitors.
GTPase-activating proteins for the ADP-ribosylation factors (ARFGAPs) play important roles in many biological processes, including vesicle trafficking and cytoskeleton reorganization. We recently identified a small molecule ARFGAP inhibitor from a high throughput chemical screen of the Wnt signaling pathway. We are exploring the functions and mode of actions of this molecule in membrane trafficking, cell migration, and neurite
1. Zhang, Q.; Major, B.; Takanashi, S.; Camp, N. D.; Nishiya, N.; Peters, E. C.; Ginsberg, M.; Schultz, P. G.; Moon, R. T.; Ding, S. A Small Molecule Synergist of the Wnt/β-catenin Signaling Pathway. Proc. Natl. Acad. Sci. U. S. A. 2007, 104, 7444–7448.
2. Chen, S.; Takanashi, S.; Zhang, Q.; Xiong, W.; Peters, E.C.; Ding, S.; Schultz, P.G. Reversine Induces Cellular Reprogramming of Lineage-Committed Mammalian Cells. Proc. Natl. Acad. Sci. U. S. A. 2007, 104, 10482-10487.
3. Song, Z. and Zhang, Q. Fluorous Aryl Diazirine Photoaffinity Labeling Reagents. Org. Lett. 2009, 11, 4883-4885.
4. Jones, C. A.; Nishiya, N.; London, N. R.; Zhu, W.; Sorensen, L. K.; Chan, A.; Lim, C. J.; Chen, H.; Zhang, Q.; Schultz, P. G.; Hayallah, A. M.; Thomas, K. R.; Famulok, M.; Zhang, K.; Ginsberg, M. H.; Li, D. Y. Slit2-Robo4 Signaling Promotes Vascular Stability by Blocking Arf6 Activity. Nature Cell Biol. 2009, 11, 1325-1331.
5. Liu, R.; Xu, R.; Chen, M.; Weiwer, M.; Zhou, X.; Bridges, A. S.; DeAngelis, P. L.; Zhang, Q.; Linhardt, R. J.; Liu, J. Chemoenzymatic Design of Heparan Sulfate Oligosaccharides. J. Biol. Chem. 2010, 285, 34240-34249.
6. Huang, W.; Hicks, S. N.; Sondek, J.; Zhang, Q. A Fluorogenic, Small Molecule Reporter for Mammalian Phospholipase C Isozymes. ACS Chem. Biol. 2011, 6, 223-228.
7. Sun, W.; Vanhooke, J.; Sondek, J.; Zhang, Q. High Throughput Fluorescence Polarization Assay for the Enzymatic Activity of GTPase-activating Protein of ADP-ribosylation Factor (ARFGAP). J. Biomol. Screen. 2011, 16, 717-723.
8. Huang, W.; Jiang, D.; Wang, X.; Sims, C. E.; Allbritton, N. L.; Zhang, Q. Kinetic Analysis of PI3K Reactions with Fluorescent PIP2 Derivatives. Anal. Bioanal. Chem. 2011, 401, 1881-1888.
9. Song, Z.; Zhang, Q. Design, Synthesis, and Incorporation of Fluorous 5-Methylcytosines into Oligonucleotides. J. Org. Chem. 2011, 76, 10263-10268.
10. Song, Z.; Huang, W.; Zhang, Q. Isotope-coded, Fluorous Photoaffinity Labeling Reagents. Chem. Commun. 2012, 48, 3339-3341.
11. Huang, W.; Sun, W.; Song, Z.; Yu, Y.; Chen, X.; Zhang, Q. Incorporation of a Fluorous Diazirine Group into Phosphatidylinositol 4,5-Bisphosphate to Illustrate its Interaction with ADP-ribosylation Factor 1. Org. Biomol. Chem. 2012, 10, 5197-5201.
12. Wang, X.; Barrett, M.; Sondek, J.; Harden, T. K.; Zhang, Q. Fluorescent Phosphatidylinositol 4,5-Bisphosphate Derivatives with Modified 6-Hydroxy Group as Novel Substrates for Phospholipase C. Biochemistry 2012, 51, 5300-5306.
13. Huang, W.; Barrett, M.; Hajicek, N.; Hicks, S.; Harden, T. K.; Sondek, J.; Zhang, Q. Small Molecule Inhibitors of Phospholipase C from a Novel High-throughput Screen. J. Biol. Chem. 2013, 288, 5840-5848.
14. Huang, W.; Proctor, A.; Sims, C. E.; Allbritton, N. L.; Zhang, Q. Fluorous Enzymatic Synthesis of Phosphatidylinositides. Chem. Commun. 2014, 50, 2928-2931.
15. Charpentier, T. H.; Waldo, G. L.; Barrett, M. O.; Huang, W.; Zhang, Q.; Harden, T. K.; Sondek, J. Membrane-induced Allosteric Control of Phospholipase C-beta Isozymes. J. Biol. Chem. 2014, in press.
A postdoc position in Cell Biology is available immediately in the lab. The broad objective of the project is to understand the cellular functions and mechanisms of small molecules that monitor and regulate lipid signaling, particularly those related to phosphatidylinositides and small GTPases. To be considered, applicants must have a Ph.D. in Cell Biology or a related field. Experience with cell signaling studies is required and expertise in microscopy is preferred. Compensation is commensurate with experience. Please send a detailed cover letter, curriculum vitae, and names of two references to Dr. Qisheng Zhang (firstname.lastname@example.org).
We also look for graduate students and undergraduate students who are highly motivated, open-minded, and enthusiastic about working on multi-disciplinary research projects to join the lab.
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Extended Scientific Family
The Zhang lab studies lipid signaling pathways that are involved in development and diseases by developing novel chemical probes and technologies. As key components of cellular membranes, lipids also serve as signaling molecules and modify functions of proteins through either covalent or non-covalent interactions.