Glutamate is the main excitatory neurotransmitter in the mammalian central nervous system and is present at high concentrations in the brain. Glutamate acts by binding to glutamate receptors on the cell surface, but is also neurotoxic if present extracellularly in high concentrations. Hence, the brain requires a quick and effective transport system to remove glutamate from the different compartments of the brain. To date, five distinct glutamate transporters have been cloned from animal and human tissue: GLAST (EEAT1), GLT (EAAT2), EAAC (EAAT3), EAAT4 and EAAT5 (Struck et al., 1992; Kanai and Hediger, 1992; Pines et al., 1992; Fairman et al., 1995; Arriza et al., 1997). GLAST and GLT are located primarily in astrocytes, whereas EAAC, EAAT4 and EAAT5 are neuronal.
In my thesis I have given a brief overview of the glutamate transporters in the central nervous system and presented the work I have done in mapping a potential interacting protein to the quantitatively dominating glutamate transporter, GLT. Previously it has been shown that another glutamate transporter, EAAT4 which is primarily localized to the cerebellum, has two interacting proteins (GTRAP41 and GTRAP48). These proteins anchor and modulate the function and uptake efficiency of this transporter (Jackson et al., 2001). Similarly, my project aimed to clone and try to map a possible anchoring and/or modulating protein to GLT by using a range of molecular microbiological methods.