Identification of a possible MAP kinase cascade in Arabidopsis thaliana based on pairwise yeast two-hybrid analysis and functional complementation tests of yeast mutants

A possible MAP kinase (MAPK) cascade of Arabidopsis thaliana was identified on the basis of both yeast 2-hybrid analysis and complementation analysis of yeast mutants, Specific protein-protein interactions between ATMPK4 (a MAPK) and MEK1 (a MAPKK) and interactions between MEK1 and ATMEKK1 (a MAPKKK) were detected by using the 2-hybrid system, A growth defect of the yeast mpk1 Delta mutant was reversed by coexpression of ATMPK4 and MEK1, Coexpression of the N-terminal deletion form of ATMEKK1 increased the ability of MEK1 to suppress a growth defect of the yeast pbs2 Delta mutant, These results suggest that ATMPK4, MEK1, and ATMEKK1 may interact with each other and constitute a specific MAPK cascade in Arabidopsis. This is the first demonstration of a possible MAPK cascade in plants, (C) 1998 Federation of European Biochemical Societies.