glycogen synthase kinase 3-alpha is a multifunctional protein serine kinase, homologous to "drosophila" 'shaggy' (zeste-white3) and implicated in the control of several regulatory proteins including glycogen synthase and various transcription factors (e.g., jun). it also plays a role in the wnt and phosphoinositide 3-kinase (especially pik3cg) signaling pathways.