Gsk3 enzyme is one of the most interesting protein.  In Jope's paper about it, he showed us the caracteristic that gsk3 has of change it's way to work depending of the place that it is. If it is in the cytosolic compartiment it acts phosphorylating proteins that become active or inactive. If it is in the nucleus it acts in growing factors. Sometime thies enzyme is present in mithocondrias and acts in a survive or apoptotic way.
About this you can read Jope,2004.