T-duality and Gauge Symmetry in Supermembrane Theory

T-duality has been shown to arise from a gauge symmetry in some string theories. However, in the case of \IIA\ compactified on a circle, it is not possible to show that this is the case. This situation is rather uncomfortable since string string duality suggests that all T-dualities should arise from a gauge symmetry. Here we show that the T-duality of \IIA\ compactified on a circle arises from the reparametrization of the supermembrane. Then we show how this reparametrization can be understood in terms of a gauge symmetry of the supermembrane, thus allowing to connect T-duality in \II\ to a gauge symmetry of the supermembrane.