以上结果已于2007年在J Biol Chem杂志上发表，为AMPK的自抑制机制提出的重要的理论假设和实验证据。该论文在相关领域引起关注，目前已被发表于Nature、Nat Rev Mol Cell Biol、EMBO J、J Biol Chem、BBRC等6篇论文引用。
Conserved -Helix Acts as Autoinhibitory Sequence in AMP-activated Protein Kinase Subunits
Pang T, Xiong B, Li JY, Qiu BY, Jin GZ, Shen JK, Li J*.
J. Biol. Chem. (IF: 5.808)
Vol. 282, No. 1, pp. 495–506, January 5, 2007
AMP-activated protein kinase (AMPK) acts as an energy sensor, being activated by metabolic stresses and regulating cellular metabolism. AMPK is a heterotrimer consisting of a catalytic subunit and two regulatory subunits, and . It had been reported that the mammalian AMPK subunit contained an autoinhibitory domain ( 1: residues 313-392) and had little kinase activity. We have found that a conserved short segment of the subunit ( 1-(313-335)), which includes a predicted -helix, is responsible for subunit autoinhibition. The role of the residues in this segment for autoinhibition was further investigated by systematic site-directed mutation. Several hydrophobic and charged residues, in particular Leu-328, were found to be critical for 1 autoinhibition. An autoinhibitory structural model of human AMPK 1-(1-335) was constructed and revealed that Val-298 interacts with Leu-328 through hydrophobic bonding at a distance of about 4 Å and may stabilize the autoinhibitory conformation. Further mutation analysis showed that V298G mutation significantly activated the kinase activity. Moreover, the phosphorylation level of acetyl-CoA carboxylase, the AMPK downstream substrate, was significantly increased in COS7 cells overexpressing AMPK 1-(1-394) with deletion of residues 313-335 ( 394) and a V298G or L328Q mutation, and the glucose uptake was also significantly enhanced in HepG2 cells transiently transfected with 394, V298G, or L328Q mutants, which indicated that these AMPK 1 mutants are constitutively active in mammalian cells and that interaction between Leu-328 and Val-298 plays an important role in AMPK autoinhibitory function.