Effect of different γ-subunit isoforms on the regulation of AMPK.
AMP-activated protein kinase (AMPK) plays a key role in integrating metabolic pathways in response to energy demand. AMPK activation results in a wide range of downstream responses, many of which are associated with improved metabolic outcome, making AMPK an attractive target for the treatment of metabolic diseases. AMPK is a heterotrimeric complex consisting of a catalytic subunit (α) and two regulatory subunits (β and γ). The γ-subunit harbours the nucleotide-binding sites and plays an important role in AMPK regulation in response to cellular energy levels. In mammals, there are three isoforms of the γ-subunit and these respond differently to regulation by nucleotides, but there is limited information regarding their role in activation by small molecules. Here, we determined the effect of different γ-isoforms on AMPK by a direct activator, 991. In cells, 991 led to a greater activation of γ2-containing AMPK complexes compared with either γ1 or γ3. This effect was dependent on the long N-terminal region of the γ2-isoform. We were able to rule out an effect of Ser108 phosphorylation, since mutation of Ser108 to alanine in the β2-isoform had no effect on activation of AMPK by 991 in either γ1- or γ2-complexes. The rate of dephosphorylation of Thr172 was slower for γ2- compared with γ1-complexes, both in the absence and presence of 991. Our studies show that activation of AMPK by 991 depends on the nature of the γ-isoform. This finding may have implications for the design of isoform-selective AMPK activators.
['Willows|Robin|R|', 'Navaratnam|Naveenan|N|', 'Lima|Ana|A|', 'Read|Jon|J|', 'Carling|David|D|']
D055372:AMP-Activated Protein Kinases D000494:Allosteric Regulation D019943:Amino Acid Substitution D000631:Aminopyridines D001562:Benzimidazoles D001565:Benzoates D001665:Binding Sites D064113:CRISPR-Cas Systems D004789:Enzyme Activation D020536:Enzyme Activators D057809:HEK293 Cells D006801:Humans D007211:Indoles D007527:Isoenzymes D008024:Ligands D009154:Mutation D010766:Phosphorylation D011499:Protein Processing, Post-Translational D011994:Recombinant Proteins D013912:Threonine
AMPK metabolic regulation protein–serine–threonine kinases