This green structure we call rats. And rats is basically a small g protein. It basically allows the binding of GDP molecules and GTP molecules. And just like the g proteins we spoke of in the previous lectures, this small g protein in its inactive state binds GDP. And in its active state it binds GTP. And so what happens is once two the SOS binds onto one, the GRB two that activates this protein called SOS, showed in purple, that allows it to bind this Ras.