Substrate recognition determinants of human eIF2α phosphatases

Phosphorylation of the translation initiation factor eIF2α is a rapid and vital cellular defence against many forms of stress. In mammals, the levels of eIF2α phosphorylation are set through the antagonistic action of four protein kinases and two heterodimeric protein phosphatases. The phosphatases...

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Autores principales:	George Hodgson, Antonina Andreeva, Anne Bertolotti
Formato:	article
Lenguaje:	EN
Publicado:	The Royal Society 2021
Materias:	phosphatase PP1 PPP1R15 integrated stress response eIF2α phosphorylation Biology (General) QH301-705.5
Acceso en línea:	https://doaj.org/article/2ebf25ba0e42406a8cb5e2913927c95c
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spelling	oai:doaj.org-article:2ebf25ba0e42406a8cb5e2913927c95c2021-12-02T14:47:01ZSubstrate recognition determinants of human eIF2α phosphatases10.1098/rsob.2102052046-2441https://doaj.org/article/2ebf25ba0e42406a8cb5e2913927c95c2021-12-01T00:00:00Zhttps://royalsocietypublishing.org/doi/10.1098/rsob.210205https://doaj.org/toc/2046-2441Phosphorylation of the translation initiation factor eIF2α is a rapid and vital cellular defence against many forms of stress. In mammals, the levels of eIF2α phosphorylation are set through the antagonistic action of four protein kinases and two heterodimeric protein phosphatases. The phosphatases are composed of the catalytic subunit PP1 and one of two related non-catalytic subunits, PPP1R15A or PPP1R15B (R15A or R15B). Here, we generated a series of R15 truncation mutants and tested their properties in mammalian cells. We show that substrate recruitment is encoded by an evolutionary conserved region in R15s, R15A325–554 and R15B340–639. G-actin, which has been proposed to confer selectivity to R15 phosphatases, does not bind these regions, indicating that it is not required for substrate binding. Fragments containing the substrate-binding regions but lacking the PP1-binding motif trapped the phospho-substrate and caused accumulation of phosphorylated eIF2α in unstressed cells. Activity assays in cells showed that R15A325–674 and R15B340–713, encompassing the substrate-binding region and the PP1-binding region, exhibit wild-type activity. This work identifies the substrate-binding region in R15s, that functions as a phospho-substrate trapping mutant, thereby defining a key region of R15s for follow up studies.George HodgsonAntonina AndreevaAnne BertolottiThe Royal SocietyarticlephosphatasePP1PPP1R15integrated stress responseeIF2α phosphorylationBiology (General)QH301-705.5ENOpen Biology, Vol 11, Iss 12 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	phosphatase PP1 PPP1R15 integrated stress response eIF2α phosphorylation Biology (General) QH301-705.5
spellingShingle	phosphatase PP1 PPP1R15 integrated stress response eIF2α phosphorylation Biology (General) QH301-705.5 George Hodgson Antonina Andreeva Anne Bertolotti Substrate recognition determinants of human eIF2α phosphatases
description	Phosphorylation of the translation initiation factor eIF2α is a rapid and vital cellular defence against many forms of stress. In mammals, the levels of eIF2α phosphorylation are set through the antagonistic action of four protein kinases and two heterodimeric protein phosphatases. The phosphatases are composed of the catalytic subunit PP1 and one of two related non-catalytic subunits, PPP1R15A or PPP1R15B (R15A or R15B). Here, we generated a series of R15 truncation mutants and tested their properties in mammalian cells. We show that substrate recruitment is encoded by an evolutionary conserved region in R15s, R15A325–554 and R15B340–639. G-actin, which has been proposed to confer selectivity to R15 phosphatases, does not bind these regions, indicating that it is not required for substrate binding. Fragments containing the substrate-binding regions but lacking the PP1-binding motif trapped the phospho-substrate and caused accumulation of phosphorylated eIF2α in unstressed cells. Activity assays in cells showed that R15A325–674 and R15B340–713, encompassing the substrate-binding region and the PP1-binding region, exhibit wild-type activity. This work identifies the substrate-binding region in R15s, that functions as a phospho-substrate trapping mutant, thereby defining a key region of R15s for follow up studies.
format	article
author	George Hodgson Antonina Andreeva Anne Bertolotti
author_facet	George Hodgson Antonina Andreeva Anne Bertolotti
author_sort	George Hodgson
title	Substrate recognition determinants of human eIF2α phosphatases
title_short	Substrate recognition determinants of human eIF2α phosphatases
title_full	Substrate recognition determinants of human eIF2α phosphatases
title_fullStr	Substrate recognition determinants of human eIF2α phosphatases
title_full_unstemmed	Substrate recognition determinants of human eIF2α phosphatases
title_sort	substrate recognition determinants of human eif2α phosphatases
publisher	The Royal Society
publishDate	2021
url	https://doaj.org/article/2ebf25ba0e42406a8cb5e2913927c95c
work_keys_str_mv	AT georgehodgson substraterecognitiondeterminantsofhumaneif2aphosphatases AT antoninaandreeva substraterecognitiondeterminantsofhumaneif2aphosphatases AT annebertolotti substraterecognitiondeterminantsofhumaneif2aphosphatases
_version_	1718389557909520384

Substrate recognition determinants of human eIF2α phosphatases

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