5′-AMP inhibits dephosphorylation, as well as promoting phosphorylation, of the AMP-activated protein kinase. Studies using bacterially expressed human protein …

SP Davies, NR Helps, PTW Cohen, DG Hardie - FEBS letters, 1995 - Elsevier
SP Davies, NR Helps, PTW Cohen, DG Hardie
FEBS letters, 1995Elsevier
Human protein phosphatase-2Cα (PP2Cα) was purified to homogeneity after expression in
Escherichia coli. AMP inhibited the dephosphorylation of AMP-activated protein kinase
(AMPK), but not phosphocasein, by PP2Cα. The concentration dependence and the effects
of other nucleotides (ATP and formycin A-5′-monophosphate) suggest that AMP acts by
binding to the same site which causes direct allosteric activation of AMPK. A similar,
although less pronounced, effect was observed with another protein phosphatase (PP2Ac) …
Human protein phosphatase-2Cα (PP2Cα) was purified to homogeneity after expression in Escherichia coli. AMP inhibited the dephosphorylation of AMP-activated protein kinase (AMPK), but not phosphocasein, by PP2Cα. The concentration dependence and the effects of other nucleotides (ATP and formycin A-5′-monophosphate) suggest that AMP acts by binding to the same site which causes direct allosteric activation of AMPK. A similar, although less pronounced, effect was observed with another protein phosphatase (PP2Ac). We have now shown that AMPK activates the AMPK cascade by four mechanisms, which should make the system exquisitely sensitive to changes in AMP concentration.
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