There is a separate check-in area for shuttle located just to the right of the skypriority counter. There is NOT a separate shuttle security line... there was a few years ago before security got rearranged around and precheck was put in.

So currently your security option for the shuttle is to hit the precheck lottery and be through and at the gate in under 5 min, or have to wait in the sometimes long 'elite' security line. As mentioned earlier, shuttle gates are on the 'main' side of the terminal so is just down the hall after you clear security.