A novel AMPK activator, PT‐1, increases gamma1 AMPKassociated activity, but not gamma3 AMPK‐associated activity or glucose transport

AMP activated protein kinase (AMPK) is a heterotrimeric αβγ complex. Selective pharmacological activation of specific AMPK‐complexes through targeting of its regulatory subunits is an attractive strategy to confine AMPK activation to select tissues to combat diseases such as type 2 Diabetes. Furthermore, it is a useful tool to study specific AMPK complexes in vivo. Here, a putative direct α‐AMPK specific activator, PT‐1, was found to selectively increase γ1, but not γ3 AMPK‐associated activity in incubated mouse muscles. In contrast, the AMP‐mimetic AMPK activator, AICAR stimulated both γ1 and γ3 AMPK activities. Both PT‐1 and AICAR augmented AMPK Thr172 phosphorylation when measured in whole muscle lysates. However, unlike AICAR, PT‐1 did not increase TBC1D1 Ser237 or ACCbeta Ser221 phosphorylation, suggesting that these phosphorylations are catalyzed by γ3 but not γ1‐AMPK complexes. Unlike AICAR, known to require α2,β2 and γ3 AMPK to increase glucose transport, PT‐1 failed to stimulate this process. In summary, this study demonstrates for the first time γ1‐ but not γ3‐AMPK activation by PT‐1. TBC1D1 Ser237, ACCbeta Ser221 and glucose transport‐stimulation reflect α2β2γ3‐ but not γ1‐AMPK activity in mouse muscle. Funded by Danish Research Council and Novo Nordisk Foundation.