GSK3

GSK-3 (zw3 or shaggy in Drosophila) is a key enzyme in Wnt signaling. It phosphorylates b-catenin leading to the subsequent degradation of this molecule. The phosphorylation is primed by CK1alpha (Liu, 2002).

There are two human and mouse GSK3 genes and they are redundant (Doble 2007).

Phosphorylation of the tail of LRP is regulated by two protein kinases: GSK3 and CK1gamma (Zeng, 2005; Davidson 2005; reviewed by Nusse, 2005 .

GSK also phosphorylates the Wnt components Axin (Behrens, 1998) APC (Hart, 1998) and TCF (Lee, 2001)

GSK3 has multiple non-wnt related functions: it is involved in insulin signaling, NFAT phosphorylation and also in Hedgehog signaling (Price 2002).

• See pathway and interaction figures.

• The structure of GSK3 beta has been determined, and there is structural information on the GSK-Axin complex (Dajani 2003)