NatB-mediated N-terminal acetylation affects growth and biotic stress responses
N∝-terminal acetylation (NTA) is one of the most abundant protein modifications in eukaryotes. In humans, NTA is catalyzed by seven Nα-acetyltransferases (NatA-F and NatH). Remarkably, the plant Nat machinery and its biological relevance remain poorly understood, although NTA has gained recognition...
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| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
[February 2020]
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| In: |
Plant physiology
Year: 2020, Volume: 182, Issue: 2, Pages: 792-806 |
| ISSN: | 1532-2548 |
| DOI: | 10.1104/pp.19.00792 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1104/pp.19.00792 Verlag, lizenzpflichtig, Volltext: http://www.plantphysiol.org/content/182/2/792 
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| Author Notes: | Monika Huber, Willy V. Bienvenut, Eric Linster, Iwona Stephan, Laura Armbruster, Carsten Sticht, Dominik Layer, Karine Lapouge, Thierry Meinnel, Irmgard Sinning, Carmela Giglione, Ruediger Hell, Markus Wirtz |
| Summary: | N∝-terminal acetylation (NTA) is one of the most abundant protein modifications in eukaryotes. In humans, NTA is catalyzed by seven Nα-acetyltransferases (NatA-F and NatH). Remarkably, the plant Nat machinery and its biological relevance remain poorly understood, although NTA has gained recognition as a key regulator of crucial processes such as protein turnover, protein-protein interaction, and protein targeting. In this study, we combined in vitro assays, reverse genetics, quantitative N-terminomics, transcriptomics, and physiological assays to characterize the Arabidopsis (Arabidopsis thaliana) NatB complex. We show that the plant NatB catalytic (NAA20) and auxiliary subunit (NAA25) form a stable heterodimeric complex that accepts canonical NatB-type substrates in vitro. In planta, NatB complex formation was essential for enzymatic activity. Depletion of NatB subunits to 30% of the wild-type level in three Arabidopsis T-DNA insertion mutants (naa20-1, naa20-2, and naa25-1) caused a 50% decrease in plant growth. A complementation approach revealed functional conservation between plant and human catalytic NatB subunits, whereas yeast NAA20 failed to complement naa20-1. Quantitative N-terminomics of approximately 1000 peptides identified 32 bona fide substrates of the plant NatB complex. In vivo, NatB was seen to preferentially acetylate N termini starting with the initiator Met followed by acidic amino acids and contributed 20% of the acetylation marks in the detected plant proteome. Global transcriptome and proteome analyses of NatB-depleted mutants suggested a function of NatB in multiple stress responses. Indeed, loss of NatB function, but not NatA, increased plant sensitivity toward osmotic and high-salt stress, indicating that NatB is required for tolerance of these abiotic stressors. |
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| Item Description: | Gesehen am 30.03.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1532-2548 |
| DOI: | 10.1104/pp.19.00792 |