The mitogen-activated protein kinase 4-phosphorylated heat shock factor A4A regulates responses to combined salt and heat stresses

Andrási, Norbert and Rigó, Gábor and Zsigmond, Laura and Pérez-Salamó, Imma and Papdi, Csaba and Klement, Éva and Pettkó-Szandtner, Aladár and Cséplő, Ágnes and Szabados, László (2019) The mitogen-activated protein kinase 4-phosphorylated heat shock factor A4A regulates responses to combined salt and heat stresses. JOURNAL OF EXPERIMENTAL BOTANY, 70 (18). pp. 4903-4917. ISSN 0022-0957 (print); 1460-2431 (online)

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Heat shock factors regulate responses to high temperatures, salinity, water deprivation or heavy metals. Their function in stress combinations is however not known. The Arabidopsis HEAT SHOCK FACTOR A4A (HSFA4A) was previously reported to regulate responses to salt and oxidative stresses. Here we show, that the HSFA4A gene is induced by salt, elevated temperature and combination of these conditions. Fast translocation of HSFA4A-YFP protein from cytosol to nuclei takes place in salt-treated cells. HSFA4A can be phosphorylated not only by MAP kinases MPK3/6 but also by MPK4 and Ser309 is the dominant MAPK phosphorylation site. In vivo data suggest that HSFA4A can be substrate of other kinases as well. Changing Ser309 to Asp or Ala has altered intramolecular multimerization. Chromatin immunoprecipitation assays confirmed binding of HSFA4A to promoters of target genes encoding the small heat shock protein HSP17.6A and transcription factors WRKY30 and ZAT12. HSFA4A overexpression enhanced tolerance to individually and simultaneously applied heat and salt stresses through reduction of oxidative damage. Our results suggest that this heat shock factor is a component of a complex stress regulatory pathway, connecting upstream signals mediated by MAP kinases MPK3/6 and MPK4 with transcription regulation of a set of stress-induced target genes.

Item Type: Article
Uncontrolled Keywords: Arabidopsis, combined stress, heat, heat shock factor A4A, MAP kinases, phosphorylation, promoter binding, salinity, transcription regulation
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3011 Biochemistry / biokémia
Depositing User: MTMT SWORD
Date Deposited: 19 Nov 2019 13:52
Last Modified: 19 Nov 2019 13:52

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