Abstract
We have elucidated that AtMPK4 was involved in cytokinesis in Arabidopsis. The ANQ/AtMKK6 MAPKK activated AtMPK4 specifically in vitro. And, we investigated the activity of AtMPK4 in the anq mutant using immnocomplex kinase assay with anti-AtMPK4 antibody, and that activity was reduced. Furthermore, it was observed that multinucleate cells with incomplete cell plates in the root and the leaf in the atmpk4 mutant. These results suggest that AtMPK4 regulates the growth of cell plate positively downstream of ANQ. But, the atmpk4-2 mutant was not lethal, we postulated that other MAPK also might regulate cytokinesis. To investigate this possibility, we observed the phenotype of atmpk11 mutant with atmpk4-2 mutation.
