TLR and TNF-R1 activation of the MKK3/MKK6–p38α axis in macrophages is mediated by TPL-2 kinase
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Previous studies suggested that Toll-like receptor (TLR) stimulation of the p38α MAP kinase (MAPK) is mediated by transforming growth factor-β-activated kinase 1 (TAK1) activation of MAPK kinases, MKK3, MKK4 and MKK6. We used quantitative mass spectrometry to monitor tumour progression locus 2 (TPL-2)-dependent protein phosphorylation following TLR4 stimulation with lipopolysaccharide, comparing macrophages from wild-type mice and Map3k8D270A/D270A mice expressing catalytically inactive TPL-2 (MAP3K8). In addition to the established TPL-2 substrates MKK1/2, TPL-2 kinase activity was required to phosphorylate the activation loops of MKK3/6, but not of MKK4. MKK3/6 activation required IκB kinase (IKK) phosphorylation of the TPL-2 binding partner nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB1) p105, similar to MKK1/2 activation. Tumour necrosis factor (TNF) stimulation of MKK3/6 phosphorylation was similarly dependent on TPL-2 catalytic activity and IKK phosphorylation of NF-κB1 p105. Owing to redundancy of MKK3/6 with MKK4, Map3k8D270A mutation only fractionally decreased lipopolysaccharide activation of p38α. TNF activation of p38α, which is mediated predominantly via MKK3/6, was substantially reduced. TPL-2 catalytic activity was also required for MKK3/6 and p38α activation following macrophage stimulation with Mycobacterium tuberculosis and Listeria monocytogenes. Our experiments demonstrate that the IKK/NF-κB1 p105/TPL-2 signalling pathway, downstream of TAK1, regulates MKK3/6 and p38α activation in macrophages in inflammation.
Date Issued
2016-09-15
Date Acceptance
2016-07-11
Citation
Biochemical Journal, 2016, 473 (18), pp.2845-2861
ISSN
0264-6021
Publisher
Portland Press Ltd.
Start Page
2845
End Page
2861
Journal / Book Title
Biochemical Journal
Volume
473
Issue
18
Copyright Statement
© 2016 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY) (https://creativecommons.org/licenses/by/4.0).
Identifier
https://portlandpress.com/biochemj/article/473/18/2845/49273/TLR-and-TNFR1-activation-of-the-MKK3MKK6p38%CE%B1-axis
Subjects
06 Biological Sciences
11 Medical and Health Sciences
03 Chemical Sciences
Biochemistry & Molecular Biology
Publication Status
Published
Date Publish Online
2016-07-11