Serine/threonine protein kinase essential for release from glucose repression via the phosphorylation of scr1 upon glucose deprivation (PubMed:22140232). Catalytic subunit of the AMP-activated protein kinase complex also known as the SNF1 kinase complex (Snf1c), a central regulator of cellular energy homeostasis, which, in response to a fall in intracellular ATP levels, activates energy-producing pathways and inhibits energy-consuming processes (PubMed:22375066). The complex phosphorylates histone H3 to form H3S10ph, which promotes H3K14ac formation, leading to transcriptional activation through TBP recruitment to the promoters (By similarity). Regulates proper cell cycle exit and sexual differentiation (PubMed:22375066). Regulates also ste11 levels under nitrogen deprivation (PubMed:22375066). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Component of the AMP-activated protein kinase complex also known as the SNF1 kinase complex (Snf1c), a heterotrimeric complex composed of a catalytic subunit alpha and 2 regulatory subunits beta (amk2) and gamma (cbs2) (PubMed:17289942, PubMed:17937917). Nuclear translocation occurs under nitrogen and glucose starvation conditions and depends on Thr-189 phosphorylation by ssp1 (PubMed:22375066). The regulatory domain (RS) also called auto-inhibitory domain (AID) inhibits kinase activity of the protein kinase domain (KD) (PubMed:19474788). The ubiquitin-associated domain (UBA) localized within the AID dampens kinase activation, probably by restraining alpha-gamma associations (By similarity). Phosphorylation at Thr-189 by ssp1 is required for nuclear entry in nutritionally stressed cells (PubMed:22375066). Prevents assimilation of glycerol and fails to induce expression of glycerol dehydrogenase gld1 on glycerol medium (PubMed:22140232). Leads to diminished mating efficiency (PubMed:22375066). Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. SNF1 subfamily.