Isolation of ATMEKK1 (a MAP kinase kinase kinase)-interacting proteins and analysis of a MAP kinase cascade in Arabidopsis

Biochem Biophys Res Commun. 1998 Dec 18;253(2):532-43. doi: 10.1006/bbrc.1998.9796.


In plants, a number of MAP kinase (MAPK), MAPK kinase (MAPKK), and MAPKK kinase (MAPKKK) homologues have been reported. However, there have been no reports of protein-protein interactions between these kinases or molecular analysis of MAPK cascades in higher plants. To analyze a possible MAPK cascade in Arabidopsis thaliana, we took two molecular approaches. One is the two-hybrid screening of ATMEKK1 (a MAPKKK)-interacting proteins; the other is an analysis of physical and functional interactions among isolated MAPK, MAPKK, and MAPKKK homologues from Arabidopsis. In two-hybrid screening using ATMEKK1 as bait, we isolated a novel MAPKK homologue, ATMKK2, a MAPK homologue, ATMPK4, and an unknown protein. ATMKK2 has high sequence similarity with MEK1 (a MAPKK) in Arabidopsis. Based on yeast two-hybrid analysis, we detected protein-protein interactions between ATMEKK1 and ATMKK2/MEK1 (MAPKKs), between ATMKK2/MEK1 and ATMPK4 (a MAPK), and between ATMPK4 and ATMEKK1. ATMPK4 and ATMKK2/MEK1 interacted with two distinct regions of ATMEKK1, the N-terminal regulatory domain and the C-terminal kinase domain, respectively. Coexpression of ATMEKK1 increased the ability of two closely related MAPKKs, ATMKK2 and MEK1, to complement a growth defect of the yeast pbs2 mutant. Coexpression of ATMPK4 and MEK1 complemented a growth defect of the yeast mpk1 and bck1 mutants. By contrast, other combinations of MAPKs and MAPKKs did not suppress these yeast mutations. These results suggest that ATMEKK1, ATMKK2/MEK1, and ATMPK4 may constitute a MAP kinase cascade.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine / genetics
  • Amino Acid Sequence
  • Amino Acid Substitution / genetics
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics*
  • Calcium-Calmodulin-Dependent Protein Kinases / biosynthesis
  • Calcium-Calmodulin-Dependent Protein Kinases / genetics
  • Calcium-Calmodulin-Dependent Protein Kinases / isolation & purification*
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism
  • Cloning, Molecular
  • DNA, Complementary / isolation & purification
  • Fungal Proteins / isolation & purification
  • Fungal Proteins / metabolism*
  • Genetic Complementation Test
  • MAP Kinase Kinase 2
  • MAP Kinase Kinase Kinases
  • Mitogen-Activated Protein Kinase Kinases*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / biosynthesis
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / isolation & purification*
  • Protein-Tyrosine Kinases / biosynthesis
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / isolation & purification
  • Threonine / genetics


  • DNA, Complementary
  • Fungal Proteins
  • Threonine
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • MAP Kinase Kinase Kinases
  • MAP Kinase Kinase 2
  • Mitogen-Activated Protein Kinase Kinases
  • Alanine

Associated data

  • GENBANK/AB015313
  • GENBANK/AB015314
  • GENBANK/AB015315
  • GENBANK/AB015316