A Conserved Loop in the Catalytic Domain of Eukaryotic Elongation Factor 2 Kinase Plays a Key Role in Its Substrate Specificity

Moore, Claire E.; Mota, Sergio Regufe da; Mikolajek, Halina; Proud, Christopher G.

doi:10.1128/mcb.00388-14

Cited by 22 publications

(27 citation statements)

References 33 publications

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“…This position corresponds to an autophosphorylation site in the related enzyme myosin heavy chain kinase (MHCK), which, when phosphorylated, docks into a binding pocket to allow the enzyme to adopt an active conformation [11] . A similar mechanism appears to apply to eEF2K [12,13] . This site can even be phosphorylated in E coli, which lacks CaM, suggesting that the activity of eEF2K in autophosphorylation is not strictly Ca/CaM dependent [13] .…”

Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 77%

“…A similar mechanism appears to apply to eEF2K [12,13] . This site can even be phosphorylated in E coli, which lacks CaM, suggesting that the activity of eEF2K in autophosphorylation is not strictly Ca/CaM dependent [13] . However, it is stimulated by Ca/CaM [13,14] .…”

Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 77%

“…This site can even be phosphorylated in E coli, which lacks CaM, suggesting that the activity of eEF2K in autophosphorylation is not strictly Ca/CaM dependent [13] . However, it is stimulated by Ca/CaM [13,14] . The conformational change associated with the phosphorylation of Thr-348 enhances eEF2K activity by increasing its affinity for a (peptide) substrate and its intrinsic catalytic activity.…”

Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 99%

“…One shared feature of those kinases and eEF2K is that this region plays a role in the binding and recognition of peptide or protein substrates. For example, point mutations within this region of eEF2K can alter its relative activity against eEF2, its physiological substrate, and a peptide substrate based on a myosin heavy chain (MH-1) [13] .…”

Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 99%

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Eukaryotic elongation factor 2 kinase as a drug target in cancer, and in cardiovascular and neurodegenerative diseases

Proud

2016

Acta Pharmacol Sin

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Eukaryotic elongation factor 2 kinase (eEF2K) is an unusual protein kinase that regulates the elongation stage of protein synthesis by phosphorylating and inhibiting its only known substrate, eEF2. Elongation is a highly energy-consuming process, and eEF2K activity is tightly regulated by several signaling pathways. Regulating translation elongation can modulate the cellular energy demand and may also control the expression of specific proteins. Growing evidence links eEF2K to a range of human diseases, including cardiovascular conditions (atherosclerosis, via macrophage survival) and pulmonary arterial hypertension, as well as solid tumors, where eEF2K appears to play contrasting roles depending on tumor type and stage. eEF2K is also involved in neurological disorders and may be a valuable target in treating depression and certain neurodegenerative diseases. Because eEF2K is not required for mammalian development or cell viability, inhibiting its function may not elicit serious side effects, while the fact that it is an atypical kinase and quite distinct from the vast majority of other mammalian kinases suggests the possibility to develop it into compounds that inhibit eEF2K without affecting other important protein kinases. Further research is needed to explore these possibilities and there is an urgent need to identify and characterize potent and specific small-molecule inhibitors of eEF2K. In this article we review the recent evidence concerning the role of eEF2K in human diseases as well as the progress in developing small-molecule inhibitors of this enzyme.

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Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 77%

Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 77%

Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 99%

Section: Overview Of the Structure And Control Of Eef2kmentioning

confidence: 99%

See 2 more Smart Citations

Eukaryotic elongation factor 2 kinase as a drug target in cancer, and in cardiovascular and neurodegenerative diseases

Proud

2016

Acta Pharmacol Sin

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“…Given the high demand of protein synthesis for cellular energy (44), it makes clear physiological sense that hypoxia should induce the phosphorylation and inhibition of eEF2 to reduce the energy needs of protein synthesis. Ideally, it would be useful to show that WT eEF2K inhibits protein synthesis to a lesser extent than Pro98Ala mutant eEF2K under normoxic conditions within cells; however, more active mutants of eEF2K inhibit their own synthesis (or that of a cotransfected reporter) and are therefore expressed at levels markedly lower than those for less active variants (25,49). This unfortunately makes it very hard to interpret the data from such experiments.…”

Section: Discussionmentioning

confidence: 97%

Elongation Factor 2 Kinase Is Regulated by Proline Hydroxylation and Protects Cells during Hypoxia

Moore

Mikolajek

Mota

et al. 2015

Molecular and Cellular Biology

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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 ␣-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. Many cells require aerobic metabolism to generate energy, necessitating an adequate supply of oxygen. Protein synthesis, especially translation elongation, is a major energy-consuming process, and translation elongation uses both ATP (for aminoacyl-tRNA charging) and GTP (at least two GTP equivalents are used during each round of the elongation process). Overall, at least four ATP equivalents are used for each amino acid added to the growing chain during elongation. Elongation rates can be regulated through the phosphorylation of eukaryotic elongation factor 2 (eEF2) (1). Phosphorylation of eEF2 on Thr56 by eEF2 kinase (eEF2K) inhibits its ability to interact with ribosomes (2), thereby impairing translation elongation. Indeed, a range of studies has shown that increased phosphorylation of eEF2 is associated with slower ribosomal movement along the mRNA (e.g., see references 3 to 5).eEF2K interacts with calmodulin (CaM) through a binding site which lies almost immediately N terminal to its catalytic domain (6, 7). The catalytic domain belongs to the small group of (six) mammalian ␣-kinases, rather than the main protein kinase superfamily; ␣-kinases show no sequence homology and only limited three-dimensional structural homology to other protein kinases (8, 9). eEF2K activity is regulated through several signaling pathways linked, e.g., to nutrient availability; these include signaling through the mammalian target of rapamycin complex 1 (mTORC1), which represses eEF2K activity, and the AMPactivated protein kinase (AMPK), a key cellular energy sensor (10) which causes activation of eEF2K (11, 12), probably in part by inhibiting mTORC1 signaling. Both inputs operate such th...

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Translational control of aberrant stress responses as a hallmark of cancer

El-Naggar

Sorensen

2018

The Journal of Pathology

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Altered mRNA translational control is emerging as a critical factor in cancer development and progression. Targeting specific elements of the translational machinery, such as mTORC1 or eIF4E, is emerging as a new strategy for innovative cancer therapy. While translation of most mRNAs takes place through cap-dependent mechanisms, a sub-population of cellular mRNA species, particularly stress-inducible mRNAs with highly structured 5'-UTR regions, are primarily translated through cap-independent mechanisms. Intriguingly, many of these mRNAs encode proteins that are involved in tumour cell adaptation to microenvironmental stress, and thus linked to aggressive behaviour including tumour invasion and metastasis. This necessitates a rigorous search for links between microenvironmental stress and aggressive tumour phenotypes. Under stress, cells block global protein synthesis to preserve energy while maintaining selective synthesis of proteins that support cell survival. One highly conserved mechanism to regulate protein synthesis under cell stress is to sequester mRNAs into cytosolic aggregates called stress granules (SGs), where their translation is silenced. SGs confer survival advantages and chemotherapeutic resistance to tumour cells under stress. Recently, it has been shown that genetically blocking SG formation dramatically reduces tumour invasive and metastatic capacity in vivo. Therefore, targeting SG formation might represent a potential treatment strategy to block cancer metastasis. Here, we present the critical link between selective mRNA translation, stress adaptation, SGs, and tumour progression. Further, we also explain how deciphering mechanisms of selective mRNA translation occurs under cell stress holds great promise for the identification of new targets in the treatment of cancer.

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A Conserved Loop in the Catalytic Domain of Eukaryotic Elongation Factor 2 Kinase Plays a Key Role in Its Substrate Specificity

Cited by 22 publications

References 33 publications

Eukaryotic elongation factor 2 kinase as a drug target in cancer, and in cardiovascular and neurodegenerative diseases

Eukaryotic elongation factor 2 kinase as a drug target in cancer, and in cardiovascular and neurodegenerative diseases

Elongation Factor 2 Kinase Is Regulated by Proline Hydroxylation and Protects Cells during Hypoxia

Translational control of aberrant stress responses as a hallmark of cancer

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