S5381-03

Rabbit Anti-Spectrin, alpha (Spectrin Non-erythroid alpha Chain, Alpha Fodrin, Alpha II Spectrin, FLJ44613, Spectrin alpha Non-erythrocytic 1, SPTAN1, SPTA2) (Not for Export EU)

Glutamate is the main excitatory neurotransmitter in the brain. To date five glutamate Transporters have been cloned: GLAST (EAAT1), GLT1 (EAAT2), EAAC1 (EAAT3), EAAT4, and EAAT5. These transporters are believed to be critical in reducing potentially toxic extracellular concentration of glutamate by rapid uptake into nerve terminals and glial cells. Synaptic vesicles in the nerve terminals play a critical role in neurotransmission. Synaptic vesicles in the nerve terminals play a critical role in neurotransmission. Glutamergic neurotransmission occurs through an exocytotic process involving the interaction of glutamate containing synaptic vesicles with the plasma membranes of the presynaptic ending. An electro-chemical proton gradient generated by a V-type H+-ATPase (vacuolar-type proton-translocating ATPase) in the synaptic vesicles membrane provides the driving force for glutamate uptake. Recently a protein, termed inhibitory protein factor (IPF), has been isolated from brain cytosol that inhibits glutamate and GABA uptake into synaptic vesicles (IC50 ~25 nM). IPF does not inhibit ATP-independent uptake, norepinephrine uptake into chromaffin vesicles, and Na-dependent glutamate uptake into synaptosomes. IPF refers to a three distinct proteins with ~mol wt of 138kDa (IPF-alpha), 135kD (IPF-beta), and 132kD (IPF-gamma). IPF-a is derived from a ubiquitous, non-erythroid brain spectrin called alpha-Fodrin, a well-characterized protein previously implicated in such diverse activities as exocytosis/endocytosis, apoptosis, and NMDA-receptor activation. However, a-Fodrin itself has no effect on glutamate uptake. The N-terminal 1-20 aa of IPF-a, IPF-b, and IPF-g are identical with 26-45 aa of a-Fodrin (mol wt ~240kD). Therefore, it appears that some identified protease(s) may generate IPF-a from a-Fodrin.