Department Affiliation: Pharmacology and Molecular Sciences
Degree: Ph.D., University of Chicago
Rank: Assistant Professor
Telephone Number: 410-502-0173; Lab: 410-614-2892
Fax Number: 410-955-3023
E-mail address: jzhang32@bs.jhmi.edu
School of Medicine Address: 307 Hunterian Building, 725 N. Wolfe St., Baltimore, MD 21205
Spatiotemporal Regulation of Protein Kinases and Second Messengers
We are interested in the spatiotemporal control of cell signaling, with a particular focus on important signaling molecules such as protein kinases and second messengers.
Recent years have seen tremendous progress in identification of signaling components constituting a network of pathways that control cellular processes. Less well developed is our understanding of how these components are precisely regulated to achieve signaling specificity within a living cell, which may be reacting to multiple inputs simultaneously. The key is believed to lie in the spatiotemporal information encoded in a particular cellular context. We are investigating the molecular basis and cellular consequences of such spatiotemporal regulation by combining biochemical and biophysical approaches, including live-cell fluorescence microscopy.
As important cellular regulators, protein kinases are often spatially compartmentalized in microdomains, and such compartmentation is widely conjectured to be a key determinant in the specificity of various signaling pathways. In order to achieve direct measurement of kinase activities, we developed a general strategy for monitoring protein phosphorylation in living cells based on fluorescence resonance energy transfer (FRET). We are currently applying several kinase reporters to investigate the spatiotemporal regulation or dysregulation of protein kinases (e.g. PKA, Akt) in cell migration, energy metabolism and cancer development. Quantitative measurement from live-cell fluorescence imaging will be combined with mechanistic computational modeling for systems analyses of signaling networks regulated by kinases.
New technology is being developed to achieve large-scale multi-dimensional profiling of kinases by integrating high-throughput capability with dynamic measurement of kinase activity. Such multi-dimensional “kinase profiling” can provide critical insights into how these important molecules are specifically controlled and intricately interconnected in different cellular systems, providing an global picture of the kinase signaling network and a better understanding of complex drug effects on an individual kinase or group of kinases. In a related endeavor, we are developing a live-cell high-throughput screening method for identification of new drug leads targeting kinases.
Another important class of cellular regulators are small molecule second messengers, which regulate various effectors including protein kinases. To decipher the cellular information encoded in the spatiotemporal dynamics of these second messengers, we set out to develop and apply biochemical and biophysical tools that allow us to monitor and perturb their dynamics with precise spatial and temporal control.
The application of these novel technologies for studying kinases and their regulators should provide a better understanding of the molecular changes that regulate the cells’ inner workings, adding time and space dimensions and dynamic information to the current map of signal transduction networks. It is our hope that these studies will eventually lead to development of more effective therapeutic treatments that target the defects arising from dysregulated kinases and second messengers.
Representative Publications:
- Newman RH and Zhang J. Visualization of Phosphatase Activity in Living Cells with a FRET-based Calcineurin Activity Sensor. Mol. BioSys. 2008; 4(6):496-501. Pub Med Reference
- Violin JD*, DiPilato LM*, Elston TC*, Yildrim N†, Zhang J†, and Lefkowitz RJ†. ?2-Adrenergic Receptor Signaling and Desensitization Elucidated by Quantitative Modeling of Real-Time cAMP Dynamics. *Equal contribution. † Co-corresponding authors J. Biol. Chem. 2008; 283(5):2949-2961 Pub Med Reference
- Allen MD and Zhang J. A Tunable FRET Circuit for Engineering Fluorescent Biosensors. Angew. Chem. Int. Ed Engl. 2008;47(3):500-2 Pub Med Reference
- Ananthanarayanan B, Fosbrink M, Rahdar M and Zhang J. Live-Cell Molecular Analysis of Akt Activation Reveals Roles for Activation Loop Phosphorylation. J. Biol. Chem. 2007; 282(50):36634-41 Pub Med Reference
- Zhang J and Allen MD. FRET-based Kinase Biosensors – Illuminating the Kinome. Mol. Biosyst. 2007; 3: 759-765 Pub Med Reference
- Allen, M.D. and Zhang, J. Subcellular dynamics of protein kinase A activity visualized by FRET-based reporters, Biochem. Biophys. Res. Commun. 348:716-721, 2006. Pub Med Reference
- Allen, M.D., DiPilato, L.M., Rahdar, M., Ren, Y.R., Chong, C., Liu, J.O. and Zhang J. Reading dynamic kinase activity in living cells for high-throughput screening, ACS Chem. Biol. 1:371-376, 2006. Pub Med Reference
- Ni, Q., Titov, D.V. and Zhang, J. Analyzing protein kinase dynamics in living cells with FRET reporters, Methods 40: 279-286, 2006. Pub Med Reference
- Ananthanarayanan B, Ni Q, and Zhang J. Signal propagation from membrane messengers to nuclear effectors revealed by reporters of phosphoinositide dynamics and Akt activity. Proc. Natl. Acad. Sci. USA 2005; 102: 15081-15086. Pub Med Reference
- DiPilato LM, Cheng X, and Zhang J. Fluorescent Indicators of cAMP and Epac Activation Reveal Differential Dynamics of cAMP Signaling within Discrete Subcellular Compartments. Proc. Natl. Acad. Sci. USA 2004; 101: 16513-16518. Pub Med Reference
Support from NIH, AHA, 3M, FAMRI, and the W.M. Keck Foundation.
Other graduate programs in which Dr. Zhang participates:
BCMB Graduate Program
Anti-Cancer Drug Development Program
Chemistry-Biology Interface Program (CBI)
Neuroscience Graduate Program
