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Activation of AMP-activated protein kinase leads to the phosphorylation of elongation factor 2 and an inhibition of protein synthesis

Activation of AMP-activated protein kinase leads to the phosphorylation of elongation factor 2 and an inhibition of protein synthesis
Activation of AMP-activated protein kinase leads to the phosphorylation of elongation factor 2 and an inhibition of protein synthesis
Protein synthesis, in particular peptide-chain elongation, consumes cellular energy. Anoxia activates AMP-activated protein kinase (AMPK, see [1]), resulting in the inhibition of biosynthetic pathways to conserve ATP. In anoxic rat hepatocytes or in hepatocytes treated with 5-aminoimidazole-4-carboxamide (AICA) riboside, AMPK was activated and protein synthesis was inhibited. The inhibition of protein synthesis could not be explained by changes in the phosphorylation states of initiation factor 4E binding protein-1 (4E-BP1) or eukaryotic initiation factor 2? (eIF2?). However, the phosphorylation state of eukaryotic elongation factor 2 (eEF2) was increased in anoxic and AICA riboside-treated hepatocytes and in AICA riboside-treated CHO-K1 cells, and eEF2 phosphorylation is known to inhibit its activity. Incubation of CHO-K1 cells with increasing concentrations of 2-deoxyglucose suggested that the mammalian target of the rapamycin (mTOR) signaling pathway did not play a major role in controlling the level of eEF2 phosphorylation in response to mild ATP depletion. In HEK293 cells, transfection of a dominant-negative AMPK construct abolished the oligomycin-induced inhibition of protein synthesis and eEF2 phosphorylation. Lastly, eEF2 kinase, the kinase that phosphorylates eEF2, was activated in anoxic or AICA riboside-treated hepatocytes. Therefore, the activation of eEF2 kinase by AMPK, resulting in the phosphorylation and inactivation of eEF2, provides a novel mechanism for the inhibition of protein synthesis.
0960-9822
1419-1423
Horman, S.
f8749f8f-0a16-4660-9027-3303b8af5fde
Browne, G.J.
3d221436-0b1f-4d4a-8965-778d3c273ff5
Krause, U.
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Patel, J.V.
89256384-4d1d-4be0-bc51-377873efaac3
Vertommen, D.
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Bertrand, L.
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Lavoinne, A.
c1b5271e-3c81-4b59-8c9a-9a020083612b
Hue, L.
a5968566-d767-4dc9-8289-97bda3574bdc
Proud, C.G.
c2cc50f9-4565-4d59-9dfc-aa70b9268a6e
Rider, M.H.
048fd0e0-8d39-4f40-8053-af812236253e
Horman, S.
f8749f8f-0a16-4660-9027-3303b8af5fde
Browne, G.J.
3d221436-0b1f-4d4a-8965-778d3c273ff5
Krause, U.
b3e36ddd-7046-4bcd-b9ee-0580f0470fe7
Patel, J.V.
89256384-4d1d-4be0-bc51-377873efaac3
Vertommen, D.
6bd40dd5-644e-4a80-9bff-26d58b0f3082
Bertrand, L.
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Lavoinne, A.
c1b5271e-3c81-4b59-8c9a-9a020083612b
Hue, L.
a5968566-d767-4dc9-8289-97bda3574bdc
Proud, C.G.
c2cc50f9-4565-4d59-9dfc-aa70b9268a6e
Rider, M.H.
048fd0e0-8d39-4f40-8053-af812236253e

Horman, S., Browne, G.J., Krause, U., Patel, J.V., Vertommen, D., Bertrand, L., Lavoinne, A., Hue, L., Proud, C.G. and Rider, M.H. (2002) Activation of AMP-activated protein kinase leads to the phosphorylation of elongation factor 2 and an inhibition of protein synthesis. Current Biology, 12 (16), 1419-1423. (doi:10.1016/S0960-9822(02)01077-1).

Record type: Article

Abstract

Protein synthesis, in particular peptide-chain elongation, consumes cellular energy. Anoxia activates AMP-activated protein kinase (AMPK, see [1]), resulting in the inhibition of biosynthetic pathways to conserve ATP. In anoxic rat hepatocytes or in hepatocytes treated with 5-aminoimidazole-4-carboxamide (AICA) riboside, AMPK was activated and protein synthesis was inhibited. The inhibition of protein synthesis could not be explained by changes in the phosphorylation states of initiation factor 4E binding protein-1 (4E-BP1) or eukaryotic initiation factor 2? (eIF2?). However, the phosphorylation state of eukaryotic elongation factor 2 (eEF2) was increased in anoxic and AICA riboside-treated hepatocytes and in AICA riboside-treated CHO-K1 cells, and eEF2 phosphorylation is known to inhibit its activity. Incubation of CHO-K1 cells with increasing concentrations of 2-deoxyglucose suggested that the mammalian target of the rapamycin (mTOR) signaling pathway did not play a major role in controlling the level of eEF2 phosphorylation in response to mild ATP depletion. In HEK293 cells, transfection of a dominant-negative AMPK construct abolished the oligomycin-induced inhibition of protein synthesis and eEF2 phosphorylation. Lastly, eEF2 kinase, the kinase that phosphorylates eEF2, was activated in anoxic or AICA riboside-treated hepatocytes. Therefore, the activation of eEF2 kinase by AMPK, resulting in the phosphorylation and inactivation of eEF2, provides a novel mechanism for the inhibition of protein synthesis.

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Published date: 20 August 2002

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Local EPrints ID: 55929
URI: http://eprints.soton.ac.uk/id/eprint/55929
ISSN: 0960-9822
PURE UUID: 250f065c-17d1-4191-955a-851c0d09c093

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Date deposited: 06 Aug 2008
Last modified: 15 Mar 2024 10:58

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Contributors

Author: S. Horman
Author: G.J. Browne
Author: U. Krause
Author: J.V. Patel
Author: D. Vertommen
Author: L. Bertrand
Author: A. Lavoinne
Author: L. Hue
Author: C.G. Proud
Author: M.H. Rider

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