I see Empty Cruise has beat me to it, but here's my 2 cents:
For jets, the maneuvering speed can be dictated by the weight, a lower IAS for a lower weight. This is to ensure the maximum G loading for the aircraft will not be exceeded. For example, the engine/pylon combination is designed for a certain G loading, so the maneouvring speed for the weight will ensure the aircraft stalls before the allowable load factor is exceeded.
For some jets, the speed is given without any reference to weight. As long as one doesn’t exceed the minimum flight weight, exceeding the G loading is not possible. But if you were to be in excess of the maximum allowable weight, and be at this published maneuvering speed, you could not exceed the strength limit of the wings by applying elevator, since the aircraft would stall first.
Maneuvering speed is also the highest speed that full aileron and rudder control can be applied without overstressing the aircraft. For rudder, that is one control input, slowly, to max deflection, and then slowly removed.
Hawk