TRANSMEMBRANE TOPOLOGY OF THE GLUTAMATE RECEPTORS - A TALE OF NOVEL TWISTS AND TURNS

The glutamate receptor subunits were first thought to cross the cell m embrane four times in a manner analogous to the neuronal nicotinic ace tylcholine, GABA(A), and glycine receptors. This model led the field f or nearly five years, although it was frequently in conflict with the data. Recently, comparisons with bacterial proteins, epitope tagging e xperiments, and the construction of chimeras has produced a new model of glutamate receptor topology that is novel and quite unlike any of t he other receptors.