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Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death

The pseudokinase mixed lineage kinase domain-like (MLKL) is an essential effector of necroptotic cell death. Two distinct human MLKL isoforms have previously been reported, but their capacities to trigger cell death have not been compared directly. Herein, we examine these two MLKL isoforms, and fur...

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Autores principales: Arnež, Katja Hrovat, Kindlova, Michaela, Bokil, Nilesh J., Murphy, James M., Sweet, Matthew J., Gunčar, Gregor
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Portland Press Ltd. 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4725247/
https://www.ncbi.nlm.nih.gov/pubmed/26704887
http://dx.doi.org/10.1042/BSR20150246
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author Arnež, Katja Hrovat
Kindlova, Michaela
Bokil, Nilesh J.
Murphy, James M.
Sweet, Matthew J.
Gunčar, Gregor
author_facet Arnež, Katja Hrovat
Kindlova, Michaela
Bokil, Nilesh J.
Murphy, James M.
Sweet, Matthew J.
Gunčar, Gregor
author_sort Arnež, Katja Hrovat
collection PubMed
description The pseudokinase mixed lineage kinase domain-like (MLKL) is an essential effector of necroptotic cell death. Two distinct human MLKL isoforms have previously been reported, but their capacities to trigger cell death have not been compared directly. Herein, we examine these two MLKL isoforms, and further probe the features of the human MLKL N-terminal domain that are required for cell death. Expression in HEK293T cells of the N-terminal 201 amino acids (aa) of human MLKL is sufficient to cause cell death, whereas expression of the first 154 aa is not. Given that aa 1–125 are able to initiate necroptosis, our findings indicate that the helix that follows this region restrains necroptotic activity, which is again restored in longer constructs. Furthermore, MLKL isoform 2 (MLKL2), which lacks much of the regulatory pseudokinase domain, is a much more potent inducer of cell death than MLKL isoform 1 (MLKL1) in ectopic expression studies in HEK293T cells. Modelling predicts that a C-terminal helix constrains the activity of MLKL1, but not MLKL2. Although both isoforms are expressed by human monocyte-derived macrophages at the mRNA level, MLKL2 is expressed at much lower levels. We propose that it may have a regulatory role in controlling macrophage survival, either in the steady state or in response to specific stimuli.
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spelling pubmed-47252472016-02-03 Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death Arnež, Katja Hrovat Kindlova, Michaela Bokil, Nilesh J. Murphy, James M. Sweet, Matthew J. Gunčar, Gregor Biosci Rep Original Papers The pseudokinase mixed lineage kinase domain-like (MLKL) is an essential effector of necroptotic cell death. Two distinct human MLKL isoforms have previously been reported, but their capacities to trigger cell death have not been compared directly. Herein, we examine these two MLKL isoforms, and further probe the features of the human MLKL N-terminal domain that are required for cell death. Expression in HEK293T cells of the N-terminal 201 amino acids (aa) of human MLKL is sufficient to cause cell death, whereas expression of the first 154 aa is not. Given that aa 1–125 are able to initiate necroptosis, our findings indicate that the helix that follows this region restrains necroptotic activity, which is again restored in longer constructs. Furthermore, MLKL isoform 2 (MLKL2), which lacks much of the regulatory pseudokinase domain, is a much more potent inducer of cell death than MLKL isoform 1 (MLKL1) in ectopic expression studies in HEK293T cells. Modelling predicts that a C-terminal helix constrains the activity of MLKL1, but not MLKL2. Although both isoforms are expressed by human monocyte-derived macrophages at the mRNA level, MLKL2 is expressed at much lower levels. We propose that it may have a regulatory role in controlling macrophage survival, either in the steady state or in response to specific stimuli. Portland Press Ltd. 2016-01-22 /pmc/articles/PMC4725247/ /pubmed/26704887 http://dx.doi.org/10.1042/BSR20150246 Text en © 2016 Authors http://creativecommons.org/licenses/by/3.0/ This is an open access article published by Portland Press Limited and distributed under the Creative Commons Attribution License 3.0 (http://creativecommons.org/licenses/by/3.0/) .
spellingShingle Original Papers
Arnež, Katja Hrovat
Kindlova, Michaela
Bokil, Nilesh J.
Murphy, James M.
Sweet, Matthew J.
Gunčar, Gregor
Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death
title Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death
title_full Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death
title_fullStr Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death
title_full_unstemmed Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death
title_short Analysis of the N-terminal region of human MLKL, as well as two distinct MLKL isoforms, reveals new insights into necroptotic cell death
title_sort analysis of the n-terminal region of human mlkl, as well as two distinct mlkl isoforms, reveals new insights into necroptotic cell death
topic Original Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4725247/
https://www.ncbi.nlm.nih.gov/pubmed/26704887
http://dx.doi.org/10.1042/BSR20150246
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