The endoplasmic reticulum transports proteins around the cell as well as sometimes to the golgi body. Not to be confused with the golgi body, the ER only transports proteins around the cytoplasm that is somewhat close to the nucleus.
The wires in a car are like the endoplasmic reticulum. The wires are mainly located around the gas tank and engine, not the areas further away from the inside of the car - the pipes. The wires of a car transports electricity that links the insides of the car to the pipes, as well as the rest of the car, just like how an ER links proteins to the rest of the cell.