7myj | pdb_00007myj
Structure of full length human AMPK (a2b1g1) in complex with a small molecule activator MSG011
Structural highlights
FunctionAAPK2_HUMAN Catalytic subunit of AMP-activated protein kinase (AMPK), an energy sensor protein kinase that plays a key role in regulating cellular energy metabolism. In response to reduction of intracellular ATP levels, AMPK activates energy-producing pathways and inhibits energy-consuming processes: inhibits protein, carbohydrate and lipid biosynthesis, as well as cell growth and proliferation. AMPK acts via direct phosphorylation of metabolic enzymes, and by longer-term effects via phosphorylation of transcription regulators. Also acts as a regulator of cellular polarity by remodeling the actin cytoskeleton; probably by indirectly activating myosin. Regulates lipid synthesis by phosphorylating and inactivating lipid metabolic enzymes such as ACACA, ACACB, GYS1, HMGCR and LIPE; regulates fatty acid and cholesterol synthesis by phosphorylating acetyl-CoA carboxylase (ACACA and ACACB) and hormone-sensitive lipase (LIPE) enzymes, respectively. Regulates insulin-signaling and glycolysis by phosphorylating IRS1, PFKFB2 and PFKFB3. AMPK stimulates glucose uptake in muscle by increasing the translocation of the glucose transporter SLC2A4/GLUT4 to the plasma membrane, possibly by mediating phosphorylation of TBC1D4/AS160. Regulates transcription and chromatin structure by phosphorylating transcription regulators involved in energy metabolism such as CRTC2/TORC2, FOXO3, histone H2B, HDAC5, MEF2C, MLXIPL/ChREBP, EP300, HNF4A, p53/TP53, SREBF1, SREBF2 and PPARGC1A. Acts as a key regulator of glucose homeostasis in liver by phosphorylating CRTC2/TORC2, leading to CRTC2/TORC2 sequestration in the cytoplasm. In response to stress, phosphorylates 'Ser-36' of histone H2B (H2BS36ph), leading to promote transcription. Acts as a key regulator of cell growth and proliferation by phosphorylating TSC2, RPTOR and ATG1: in response to nutrient limitation, negatively regulates the mTORC1 complex by phosphorylating RPTOR component of the mTORC1 complex and by phosphorylating and activating TSC2. In response to nutrient limitation, promotes autophagy by phosphorylating and activating ULK1. AMPK also acts as a regulator of circadian rhythm by mediating phosphorylation of CRY1, leading to destabilize it. May regulate the Wnt signaling pathway by phosphorylating CTNNB1, leading to stabilize it. Also phosphorylates CFTR, EEF2K, KLC1, NOS3 and SLC12A1.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] Publication Abstract from PubMedThe AMP-activated protein kinase (AMPK) alphabetagamma heterotrimer is a primary cellular energy sensor and central regulator of energy homeostasis. Activating skeletal muscle AMPK with small molecule drugs improves glucose uptake and provides an opportunity for new strategies to treat type 2 diabetes and insulin resistance, with recent genetic and pharmacological studies indicating the alpha2beta2gamma1 isoform combination as the heterotrimer complex primarily responsible. With the goal of developing alpha2beta2-specific activators, here we perform structure/function analysis of the 2-hydroxybiphenyl group of SC4, an activator with tendency for alpha2-selectivity that is also capable of potently activating beta2 complexes. Substitution of the LHS 2-hydroxyphenyl group with polar-substituted cyclohexene-based probes resulted in two AMPK agonists, MSG010 and MSG011, which did not display alpha2-selectivity when screened against a panel of AMPK complexes. By radiolabel kinase assay, MSG010 and MSG011 activated alpha2beta2gamma1 AMPK with one order of magnitude greater potency than the pan AMPK activator MK-8722. A crystal structure of MSG011 complexed to AMPK alpha2beta1gamma1 revealed a similar binding mode to SC4 and the potential importance of an interaction between the SC4 2-hydroxyl group and alpha2-Lys31 for directing alpha2-selectivity. MSG011 induced robust AMPK signalling in mouse primary hepatocytes and commonly used cell lines, and in most cases this occurred in the absence of changes in phosphorylation of the kinase activation loop residue alpha-Thr172, a classical marker of AMP-induced AMPK activity. These findings will guide future design of alpha2beta2-selective AMPK activators, that we hypothesise may avoid off-target complications associated with indiscriminate activation of AMPK throughout the body. Structure-function analysis of the AMPK activator SC4 and identification of a potent pan AMPK activator.,Ovens AJ, Gee YS, Ling NXY, Yu D, Hardee JP, Chung JD, Ngoei KRW, Waters NJ, Hoffman NJ, Scott JW, Loh K, Spengler K, Heller R, Parker MW, Lynch GS, Huang F, Galic S, Kemp BE, Baell JB, Oakhill JS, Langendorf CG Biochem J. 2022 Jun 17;479(11):1181-1204. doi: 10.1042/BCJ20220067. PMID:35552369[13] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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