|Name||Miss Maria Santiago Estevez|
|Organization||Florida International Unversity|
Interactions of Neuronal Calcium Sensor DREAM with Zinc
Maria J. Santiago Estevez and Jaroslava Miksovska
Department of Chemistry and Biochemistry
Downstream regulatory element antagonist modulator (DREAM) is an EF-hand protein that is highly expressed in the central nervous system in areas such as the hippocampus and the neural cortex and regulates kinetics of potassium channels, gene expression, calcium homeostasis and enzymatic activity of presenilin. Characterization of the metal-binding properties of DREAM and how it affects DEAM structure and DREAM interactions with effector proteins are crucial to understand its biological function under physiological and pathological conditions. Essential metals like Mg2+, Zn2+ and Ca2+ play extremely important roles in biological processes through direct interactions with proteins. DREAM carry out two Ca2+ binding EF hands and one Mg2+ binding EF hand, however little is known about DREAM binding to other biologically significant metals. Here we have monitored interactions of DREAM with Zn2+ by using intrinsic and extrinsic fluorescent probes. Our data show that Zn2+ associates to DREAM with Kd ~ 200 mM. Zn2+ does not compete for the same binding site as Ca2+ as the changes in the protein tertiary structure are distinct from those observed upon Ca2+association. Considering increased concentration of Zn2+ in neuronal tissue (150 – 200 mM), these results point towards the potential role of Zn2+ in modulating DREAM interactions with other intracellular proteins.