Mark Hernandez
Graduate Research Assistant
My Research:
We are interested in examining the role of the cytoskeleton and the caveolae in the organization and regulation of metabolism. Since joining the Hardin lab in 2005 my initial work has involved the expression caveolin-1 in lymphocytes (which normally do not express caveolins) to measure the alterations in the localizations of the glycolytic enzymes Phosphofructokinase (PFK), Aldolase (ALD), PK, and GAPDH. Previous work in the lab using 13C-NMR spectroscopy suggested that caveolin-1 transfection does not alter the rate of gluconeogenesis but decreases the rate of glycolysis. Caveolin-1 expression in lymphocytes is localized primarily at the plasma membrane and re-localizes multiple glycolytic enzymes towards the plasma membrane. With the use of confocal immunofluorescence, Metamorph linescan analysis revealed that ALD and PFK can both change distribution towards the plasma membrane in lymphocytes expressing caveolin-1. Our latest investigations have also shown that caveolin-1 plays a role in the localization of multiple glycolytic enzymes to the plasma membrane and may also play a role in the formation of a membrane-bound glycolytic compartment.
Another ongoing project will examine the role of the cytoskeleton and the caveolae in the organization and regulation of metabolism in astrocytes. Astrocytes play a critical role in a number of central nervous system activities including transmission and metabolism, and astrocytes have received considerable attention for their ability to take glucose and convert it to lactate which can then be utilized by adjacent neurons at times of energy demand. However, the role of cytoskeleton in cell metabolism has been less fully investigated. Because astrocytes can be stimulated with glutamate a potent neurotransmitter to increase glycolytic ouput, understanding the organization and regulation of the glycolytic pathway localization which allows for the production of energy near energy-consuming processes such as ion transport is critical. The cytoskeleton has been known to localize glycolytic enzymes but the role of such localization in the functional organization of glycolytic metabolism is not known is astrocytes. Therefore, it is hypothesized that the cytoskeleton and the caveolae are important in the organization and regulation of astrocyte metabolism. Some of the methods and techniques most currently used are confocal microscopy, and Western blots, and future analysis will involve cell transfections, metabolic incubations for 13C-NMR spectroscopy, and possibly PCR.
