Abstract
The AMP-activated protein kinase (AMPK) system monitors cellular energy status by sensing AMP and ATP, and is a key regulator of energy balance at the cellular and whole-body levels. AMPK exists as heterotrimeric αβγ complexes, and the γ subunits contain two tandem domains that bind the regulatory nucleotides. There is a sequence in the first of these domains that is conserved in γ subunit homologues in all eukaryotes, and which resembles the sequence around sites phosphorylated on target proteins of AMPK, except that it has a non-phosphorylatable residue in place of serine. We propose that in the absence of AMP this pseudosubstrate sequence binds to the active site groove on the α subunit, preventing phosphorylation by the upstream kinase, LKB1, and access to downstream targets. Binding of AMP causes a conformational change that prevents this interaction and relieves the inhibition. We present several lines of evidence supporting this hypothesis.
Original language | English |
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Pages (from-to) | 806-815 |
Number of pages | 10 |
Journal | The EMBO Journal |
Volume | 26 |
Issue number | 3 |
DOIs | |
Publication status | Published - 7 Feb 2007 |
Externally published | Yes |
Keywords
- AMP
- AMP-activated protein kinase
- Energy balance
- LKB1
- Pseudosubstrate