Essential role of the CD docking motif of MPK4 in plant immunity, growth, and development

Anna Siodmak, Umar F. Shahul Hameed, Naganand Rayapuram, Ronny Völz, Marie Boudsocq, Siba Alharbi, Hannah Alhoraibi, Yong Hwan Lee, Ikram Blilou, Stefan T. Arold*, Heribert Hirt*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


MAPKs are universal eukaryotic signaling factors whose functioning is assumed to depend on the recognition of a common docking motif (CD) by its activators, substrates, and inactivators. We studied the role of the CD domain of Arabidopsis MPK4 by performing interaction studies and determining the ligand-bound MPK4 crystal structure. We revealed that the CD domain of MPK4 is essential for interaction and activation by its upstream MAPKKs MKK1, MKK2, and MKK6. Cys181 in the CD site of MPK4 was shown to become sulfenylated in response to reactive oxygen species in vitro. To test the function of C181 in vivo, we generated wild-type (WT) MPK4-C181, nonsulfenylatable MPK4-C181S, and potentially sulfenylation mimicking MPK4-C181D lines in the mpk4 knockout background. We analyzed the phenotypes in growth, development, and stress responses, revealing that MPK4-C181S has WT activity and complements the mpk4 phenotype. By contrast, MPK4-C181D cannot be activated by upstream MAPKK and cannot complement the phenotypes of mpk4. Our findings show that the CD motif is essential and is required for activation by upstream MAPKK for MPK4 function. Furthermore, growth, development, or immunity functions require upstream activation of the MPK4 protein kinase.

Original languageEnglish (US)
Pages (from-to)1112-1126
Number of pages15
JournalNew Phytologist
Issue number3
StatePublished - Aug 2023

Bibliographical note

Funding Information:
We acknowledge SOLEIL for provision of synchrotron radiation facilities, and we would like to thank L. Chavas, P. Legrand, S. Sirigu, and P. Montaville for assistance in using beamline PROXIMA 1; G. Fox, M. Savko, and B. Shepard for assistance in using beamline PROXIMA 2A; and J. Perez and A. Thureau for assistance in using the beamline SWING. We would like to thank the KAUST Bioscience Corelabs for technical assistance for proteomics analysis and all members of the Hirt laboratory. For computer time, this research used the resources of the Supercomputing Laboratory at King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia. This publication is based on work supported by King Abdullah University of Science and Technology (KAUST) through the baseline fund to HH (BAS/1/1062‐01‐01) and STA (BAS/1/1056‐01‐01) and the Award no. URF/1/2965‐01 from the Office of Sponsored Research (OSR).

Publisher Copyright:
© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.


  • immunity
  • kinase activity
  • MPK4
  • oxidation
  • reactive oxygen species

ASJC Scopus subject areas

  • Physiology
  • Plant Science


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