Constitutively active protein kinase that acts as a negative regulator in the hormonal control of
glucose homeostasis, Wnt signaling and regulation of transcription factors and microtubules, by
phosphorylating and inactivating glycogen synthase (GYS1 or GYS2), CTNNB1/beta-catenin, APC and
AXIN1. Requires primed phosphorylation of the majority of its substrates. Contributes to insulin
regulation of glycogen synthesis by phosphorylating and inhibiting GYS1 activity and hence
glycogen synthesis. Regulates glycogen metabolism in liver, but not in muscle. May also mediate
the development of insulin resistance by regulating activation of transcription factors. In Wnt
signaling, regulates the level and transcriptional activity of nuclear CTNNB1/beta-catenin.
Facilitates amyloid precursor protein (APP) processing and the generation of APP-derived amyloid
plaques found in Alzheimer disease. May be involved in the regulation of replication in pancreatic
beta-cells. Is necessary for the establishment of neuronal polarity and axon outgrowth. Through
phosphorylation of the anti-apoptotic protein MCL1, may control cell apoptosis in response to
growth factors deprivation.