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.

We have a research group called GPNF in UNiversity of Faculdade de Ciências Médicas da SanTa Casa de São Paulo in São Paulo , Brazil. Our group studies Alzheimer's Disease and lithium in this disease. Our sponser Hudson Buck speake in a television program about our researches.
This speake is in this link http://www.youtube.com/watch?v=aObuymgo_3Q .

There is a lot of papers now a days presenting energy deficits as a mainly mecahanism in Alzheimer's Disease.
In these pathway our GSK3 always is present.
One of this papers is Tau Phosphorylation by GSK3 in Different Conditions, wroten by Jesús Avila et al,  in International Journal of Alzheimer’s Disease Volume 2012.
Evere day I have a huge surprise about this enzyme.