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Education: B.S. Natural Systems Department, The Defiance College, 1981 M. En. Institute of Environmental Sciences, Miami University, Ohio, 1983 Ph.D. in Botany, Miami University, Ohio, 1986 Research Interests: Plant responses to environmental stress Scientists first identified the rapid accumulation of the non-protein amino acid γ - aminobutyric acid (GABA) in plant tissues upon exposure to stress, 45 years ago. Since that time, numerous reports have documented the rapid accumulation of GABA in plant cells upon exposure to a variety of biotic or abiotic stimuli, which include heat-shock, cold-shock, darkness, touch, wounding, salinity, drought, predation, or pathogens. Surprisingly, little is known about the physiological role of GABA in higher plants. Throughout the years researchers have proposed that GABA biosynthesis is a regulator of cytosolic pH or functions as a reserve for carbon and/or nitrogen, deterrent to insect feeding and/or as a means to ameliorate the effects of free radicals. Recently scientists have suggested that GABA may function as a signaling molecule in higher plants. Several novel discoveries form the foundation of this hypothesis. One finding shows that the enzyme that synthesizes GABA from glutamate, glutamic acid decarboxylase (GAD), contains a calmodulin-binding domain (CaM-BD) and GAD activity is stimulated by Ca2+ and calmodulin (CaM) binding. Ca2+/CaM binding and enzymatic stimulation are characteristic of molecules involved in the initial stages of a signal transduction cascade. In addition, GABA also exhibits other characteristics and fulfills the criteria of being a signaling molecule. In plants, GABA (i) alters metabolism, growth, and development (ii) alters gene expression, activates enzyme(s), or induces physiological responses and (iii) may have a putative receptor or sensor molecule. The focus of the work in the laboratory is to identify and characterize the genes and proteins involved in the synthesis and sensing of glutamate (GABA precursor) and GABA in the model plant, Arabidopsis thaliana. Members of the laboratory use traditional biochemical, molecular biological, and genetic approaches; in conjunction with modern genomics, proteomics, metabolomics, bioinformatics and pharmacological approaches to identify and characterize components of the glutamate- or GABA-mediated signaling pathways. The laboratory has active research collaborations with others laboratories on The George Washington University campus such as in the Department of Pharmacology (Dr. David Perry) and in the Physics Department (Dr. Chen Zeng) and in the past with Dr. John Quackenbush (formerly at The Institute for Genomic Research, TIGR), but in the future similar research will be conducted at the GW Medical School where there is a microarray facility. Students and postdoctoral fellows are trained to conduct research in bioinformatics, molecular networking and modeling (Zeng Labortory) or on ligand/receptor binding (Perry Laboratory) or genome-wide microarray analyses.
RECENT PUBLICATIONS Kang, J., Mehta, S. and Turano, F. J. (2004) The putative glutamate receptor 1.1 (AtGLR1.1) in Arabidopsis thaliana regulates abscisic acid biosynthesis and signaling to control development and water loss. Plant Cell Physiol. 45:1380-1389. Kang, J. and Turano, F. J. (2003) The putative glutamate receptor 1.1 (AtGLR1.1) functions as a regulator of carbon and nitrogen metabolism in Arabidopsis thaliana. Proc. Nat. Acad. Sci. USA 100: 6872-6877. Turano, F. J., Muhitch, M. J., Felker, F. C. and McMahon, M. B. (2002) The putative glutamate receptor 3.2 from Arabidopsis thaliana (AtGLR3.2) is an integral membrane peptide that accumulates in rapidly growing tissues and persists in vascular-associated tissues. Plant Sci. 163:43-51. Lacombe, B., Becker, D., Hedrich , R., DeSalle, R., Hollmann, M., Kwak, J. M., Schroeder, J. I., Le Novere, N., Nam, H.-G., Spalding, E. P., Tester, M., Turano, F. J., Chiu, J. and Coruzzi, G. M. (2001) On the identity of plant glutamate receptors. Science 292:1486-1487. Turano, F. J., Panta, G. R., Allard, M. W. and van Berkum, P. (2001) The putative glutamate receptors from plants are related to two superfamilies of animal neurotransmitter receptors via distinct evolutionary mechanisms. Mol. Biol. Evol. 18:1417-1420. Coleman, S. T., Fang, T. K., Rovinsky, S. A., Turano, F. J. and Moye-Rowley, W. S. (2001) Expression of a glutamate decarboxylase homologue is required for normal oxidative stress tolerance in Saccharomyces cerevisiae J. Biol. Chem. 276:244-250. Kinnersley, A. M. and Turano, F. J. (2000) Gamma-aminobutyric acid (GABA) and plant responses to stress. Crit. Rev. Plant Sci. 19:479-509. Turano, F. J. and Muhitch, M. J. (1999) Differential accumulation of ferredoxin- and NADH-dependent glutamate synthase activities, peptides, and transcripts in developing soybean seedlings in response to light, nitrogen, and nodulation. Physiol Plant 107:407-418 Turano, F. J. (1998) Characterization of mitochondrial glutamate dehydrogenase from dark-grown soybean seedlings. Physiol. Plant. 104:337-344 Turano, F. J. and Fang, T. K. (1998) Characterization of two glutamate decarboxylase cDNA clones from Arabidopsis thaliana. Plant Physiol. 117:1411-1421 Turano, F. J., Dashner, R., Upadhyaya. A., Caldwell, C. R. and
Bauchan, G. (1998) Characterization of the glutamate dehydrogenase
isoenzyme system in germinating soybean. Plant Sci. 135:137-148 Bisc 109 - Molecular Biology, (Fall ) Bisc 105 - Plant Biochemistry (Spring, even years) Graduate: BiSc 250 - Plant Signal Transduction (Spring, odd years) Current Postdocs: Undergraduate, Graduate, and Doctoral Students Participating
in Research: Current Graduates: Sivasubramanian Balasubramanian, Department of Biological Sciences, Recent Graduates:
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