biostudies-literatureUnknown2(4)Hawley SA<h4>Background</h4>The AMP-activated protein kinase (AMPK) cascade is a sensor of cellular energy charge that acts as a 'metabolic master switch' and inhibits cell proliferation. Activation requires phosphorylation of Thr172 of AMPK within the activation loop by upstream kinases (AMPKKs) that have not been identified. Recently, we identified three related protein kinases acting upstream of the yeast homolog of AMPK. Although they do not have obvious mammalian homologs, they are related to LKB1, a tumor suppressor that is mutated in the human Peutz-Jeghers cancer syndrome. We recently showed that LKB1 exists as a complex with two accessory subunits, STRAD alpha/beta and MO25 alpha/beta.<h4>Results</h4>We report the following observations. First, two AMPKK activities purified from rat liver Journal of biology28https://www.ebi.ac.uk/biostudies/studies/S-EPMC333410biostudies-literatureComplexes between the LKB1 tumor suppressor, STRAD alpha/beta and MO25 alpha/beta are upstream kinases in the AMP-activated protein kinase cascade.PMC333410Makela TPHawley SABoudeau JMustard KJAlessi DRReid JLUdd LHardie DGfalseComplexes between the LKB1 tumor suppressor, STRAD alpha/beta and MO25 alpha/beta are upstream kinases in the AMP-activated protein kinase cascade.<h4>Background</h4>The AMP-activated protein kinase (AMPK) cascade is a sensor of cellular energy charge that acts as a 'metabolic master switch' and inhibits cell proliferation. Activation requires phosphorylation of Thr172 of AMPK within the activation loop by upstream kinases (AMPKKs) that have not been identified. Recently, we identified three related protein kinases acting upstream of the yeast homolog of AMPK. Although they do not have obvious mammalian homologs, they are related to LKB1, a tumor suppressor that is mutated in the human Peutz-Jeghers cancer syndrome. We recently showed that LKB1 exists as a complex with two accessory subunits, STRAD alpha/beta and MO25 alpha/beta.<h4>Results</h4>We report the following observations. First, two AMPKK activities purified from rat liver 2003-01-01T00:00:00Z20032025-04-18T13:59:07.576Z2019-03-27T00:50:03ZS-EPMC3334101451139410.1186/1475-4924-2-28