Faculty

Research in our laboratory focuses on protein folding mechanisms and on how misfolded proteins feature in aging and age associated diseases.  All living cells possess a group of special proteins, called heat shock proteins (HSPs), that protect cellular proteins and assist newly synthesized proteins to fold correctly.  A prominent heat shock protein is HSP70; however, its expression in old cells has been found to be defective and highly attenuated.  Previous research has indicated that the age-related reduction in HSP70 production correlates with a decreased fidelity of binding of the HSP70 transcription factor (called HSF1) to the heat shock element (HSE) on the DNA; however, the molecular origin of this defect is not known.  Work in this area has been hindered by the low abundance of HSF1 in mammalian cells as well as by the structural and functional heterogeneity of HSF1 molecules in old tissues.  To overcome these difficulties we are using novel methodologies based on single molecule spectroscopy (SMS), a technique that allows us to work with minute amounts of material (tens to hundreds of molecules), and to resolve molecular heterogeneity.  Our work aims to use the detailed structural and mechanistic information obtained by SMS to identify the molecular origin of the age related decline in the functional fidelity of HSF1 and to provide a molecular explanation for how protein aging negatively impacts transcriptional activation of target genes.

A second major thrust in our laboratory addresses mechanistic aspects of the tissue-specific production of amyloid protein deposits, the hallmark of several devastating age associated diseases including Alzheimer's and type-2 diabetes.  While the proteins that form amyloid deposits in each of these diseases differ in sequence and tertiary structure, their aggregation products are morphologically remarkably similar at the molecular level.  Our research focuses on the highly specific molecular interactions that feature in amyloid formation and aims to identify the reasons for the strong age relatedness of this deposition and to develop strategies for its inhibition.  Our most recent work addresses the potential cytotoxicity of small molecular aggregates produced by amyloid-forming peptides.  These appear early, before amyloid formation, and also serve as seeds to facilitate the process.

Representative Publications

1. Rhoades, E. and Gafni, A., "Micelle Formation by a Fragment of Human Islet Amyloid Polypeptide", Biophys. J., 2003, 84, 3480.

2. Sherman, W.A., Blouse, G.E., Perron, M.J., Tran, T., Shore, J.D. and Gafni, A., "Enthalpy measurement using calorimetry shows a significant difference in potential energy between the active and latent conformations of PAI-1", Biol. Chem., 2004, 386, 111.

3. Shi, J., Palfey, B.A., Dertouzos, J., Jensen, K.F., Gafni, A. and Steel, D.G., "Single molecule study on kinetics and mechanism of dihydroorotate dehydrogenase", J. Am. Chem. Soc., 2004, 126(22), 6914.

4. Wisser, K.C., Schauerte, J.A., Burke, D.T., Galecki, A.J., Chen, S., Miller, R.A. and Gafni, A., "Mapping tissue-specific genes correlated with age-dependent changes in protein stability and function", Arch. Biochem. Biophys., 2004, 432, 58.

5. Gafni, A., "Proteomics in aging-related research", Sci. Aging Knowl. Environ., 2004, 45, pe41.

6. Shi, J., Gafni, A. and Steel, D.G., "Application of single molecule spectroscopy in studies of enzyme kinetics and mechanisms", Meth. Enzymol., 2005, in press.