title: The Arabidopsis protein kinase Pto-interacting 1-4 is a common target of the oxidative signal-inducible 1 and mitogen-activated protein kinases.
abstract: In Arabidopsis thaliana, the serine/threonine protein kinase oxidative signal-inducible 1 (OXI1), mediates oxidative stress signalling. Its activity is required for full activation of the mitogen-activated protein kinases (MAPKs), MPK3 and MPK6, in response to oxidative stress. In addition, the serine/threonine protein kinase Pto-interacting 1-2 (PTI1-2) has been positioned downstream from OXI1, but whether PTI1-2 signals through MAPK cascades is unclear. Using a yeast two-hybrid screen we show that OXI1 also interacts with PTI1-4. OXI1 and PTI1-4 are stress-responsive genes and are expressed in the same tissues. Therefore, studies were undertaken to determine whether PTI1-4 is positioned in the OXI1/MAPK signalling pathway. The interaction between OXI1 and PTI1-4 was confirmed by using in vivo co-immunoprecipitation experiments. OXI1 and PTI1-4 were substrates of MPK3 and MPK6 in vitro. Although no direct interaction was detected between OXI1 and MPK3 or MPK6, in vitro binding studies showed interactions between MPK3 or MPK6 with PTI1-4. In addition, PTI1-4 and MPK6 were found in vivo in the same protein complex. These results demonstrate that PTI1-4 signals via OXI1 and MPK6 signalling cascades.
authors.affiliation: Max Perutz Laboratories, Vienna, Austria.
authors.forename: Celine
authors.initials: C
authors.lastname: Forzani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Carreri
authors.forename: Sergio
authors.initials: S
authors.lastname: de la Fuente van Bentem
authors.forename: David
authors.initials: D
authors.lastname: Lecourieux
authors.forename: Fatma
authors.initials: F
authors.lastname: Lecourieux
authors.forename: Heribert
authors.initials: H
authors.lastname: Hirt
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; C558535:At2g47060 protein, Arabidopsis; C482589:OXI1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases