BACKGROUND The yeast SNF1 protein kinase and the mammalian AMP-activated protein kinase are highly conserved heterotrimeric complexes that are "metabolic master switches" involved in the switch from fermentative/anaerobic to oxidative metabolism. They are activated by cellular stresses that deplete cellular ATP, and SNF1 is essential in the response to… (More)
BACKGROUND Genetic studies of Saccharomyces cerevisiae have shown that Snf1p and Snf4p, which together form the SNF1 complex, are essential for gene derepression on removal of glucose from the medium. However the metabolic signal(s) involved, and the exact role of SNF1, have remained enigmatic. Recently, the AMP-activated protein kinase (AMPK) was shown to… (More)
While allosteric activation of AMPK is triggered only by AMP, binding of both ADP and AMP has been reported to promote phosphorylation and inhibit dephosphorylation at Thr172. Because cellular concentrations of ADP and ATP are higher than AMP, it has been proposed that ADP is the physiological signal that promotes phosphorylation and that allosteric… (More)
The phenomenon whereby the presence of oxygen regulates the rate of glucose metabolism was first described by Louis Pasteur. A novel mechanism has now been discovered, involving the AMP-activated protein kinase cascade, that can account for the Pasteur effect in ischaemic heart muscle.
The AMP-activated protein kinase (AMPK) is an alphabetagamma heterotrimer that is activated by low cellular energy status and affects a switch away from energy-requiring processes and toward catabolism. While it is primarily regulated by AMP and ATP, high muscle glycogen has also been shown to repress its activation. Mutations in the gamma2 and gamma3… (More)
The γ subunits of heterotrimeric AMPK complexes contain the binding sites for the regulatory adenine nucleotides AMP, ADP and ATP. We addressed whether complexes containing different γ isoforms display different responses to adenine nucleotides by generating cells stably expressing FLAG-tagged versions of the γ1, γ2 or γ3 isoform. When assayed at a… (More)
AMPK is a sensor of cellular energy status and a promising target for drugs aimed at metabolic disorders. We have studied the selectivity and mechanism of a recently described activator, C2, and its cell-permeable prodrug, C13. C2 was a potent allosteric activator of α1-complexes that, like AMP, also protected against Thr172 dephosphorylation. Compared with… (More)
Activation of AMPK (AMP-activated protein kinase) by phosphorylation at Thr172 is catalysed by at least two distinct upstream kinases, i.e. the tumour suppressor LKB1, and CaMKKbeta (Ca2+/calmodulin-dependent protein kinase kinase-beta). The sequence around Thr172 is highly conserved between the two catalytic subunit isoforms of AMPK and the 12 AMPK-related… (More)