A CELL-CYCLE-REGULATED MAP KINASE WITH A POSSIBLE ROLE IN CYTOKINESISIN TOBACCO CELLS

Mitogen-activated protein (MAP) kinases have been demonstrated to have a role in meiosis but their involvement in mitotic events is less cle ar. Using a peptide antibody raised against the tobacco MAP kinase p43 (Ntf6) and extracts from synchronized tobacco cell suspension cultures , we show that this kinase is activated specifically during mitosis, E ntry into mitosis appears to be necessary for the activation of the ki nase, which occurs as a post-translational event. The activation of th e kinase occurs in late anaphase/early telophase. The p43Ntf6 protein shows a transient localization to the cell plate in anaphase cells, in the middle of the two microtubule arrays characteristic of the phragm oplast, a plant-specific structure involved in laying down the new cel l wall. The combined data support a role for the MAP kinase p43(Ntf6) in cytokinesis in tobacco cells.