title: Elongation Factor 2 Kinase Is Regulated by Proline Hydroxylation and Protects Cells during Hypoxia.
abstract: Protein synthesis, especially translation elongation, requires large amounts of energy, which is often generated by oxidative metabolism. Elongation is controlled by phosphorylation of eukaryotic elongation factor 2 (eEF2), which inhibits its activity and is catalyzed by eEF2 kinase (eEF2K), a calcium/calmodulin-dependent α-kinase. Hypoxia causes the activation of eEF2K and induces eEF2 phosphorylation independently of previously known inputs into eEF2K. Here, we show that eEF2K is subject to hydroxylation on proline-98. Proline hydroxylation is catalyzed by proline hydroxylases, oxygen-dependent enzymes which are inactivated during hypoxia. Pharmacological inhibition of proline hydroxylases also stimulates eEF2 phosphorylation. Pro98 lies in a universally conserved linker between the calmodulin-binding and catalytic domains of eEF2K. Its hydroxylation partially impairs the binding of calmodulin to eEF2K and markedly limits the calmodulin-stimulated activity of eEF2K. Neuronal cells depend on oxygen, and eEF2K helps to protect them from hypoxia. eEF2K is the first example of a protein directly involved in a major energy-consuming process to be regulated by proline hydroxylation. Since eEF2K is cytoprotective during hypoxia and other conditions of nutrient insufficiency, it may be a valuable target for therapy of poorly vascularized solid tumors.
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom.
authors.forename: Claire E J
authors.initials: CE
authors.lastname: Moore
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom.
authors.forename: Halina
authors.initials: H
authors.lastname: Mikolajek
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom.
authors.forename: Sergio
authors.initials: S
authors.lastname: Regufe da Mota
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom.
authors.forename: Xuemin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom.
authors.forename: Justin W
authors.initials: JW
authors.lastname: Kenney
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom.
authors.forename: Jörn M
authors.initials: JM
authors.lastname: Werner
authors.affiliation: Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom christopher.proud@sahmri.com.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Proud
mesh_terms: D000818:Animals; D002147:Calmodulin / Q000378:metabolism; D020134:Catalytic Domain; D015687:Cell Hypoxia; D002478:Cells, Cultured; D054736:Elongation Factor 2 Kinase / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D045325:HCT116 Cells; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D006900:Hydroxylation; D051379:Mice; D009474:Neurons / Q000201:enzymology*; D020652:Peptide Elongation Factor 2 / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011392:Proline / Q000378:metabolism*; D064828:Prolyl Hydroxylases / Q000378:metabolism; D064800:Prolyl-Hydroxylase Inhibitors / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D020652:Peptide Elongation Factor 2; D064800:Prolyl-Hydroxylase Inhibitors; D011392:Proline; D064828:Prolyl Hydroxylases; C517689:EEF2K protein, human; C517690:Eef2k protein, mouse; D054736:Elongation Factor 2 Kinase