NQK1/NtMEK1 is a MAPKK that acts in the NPK1 MAPKKK-mediated MAPK cascade and is required for plant cytokinesis.

ABSTRACT: The tobacco protein kinase NPK1 is a MAPKKK that regulates formation of the cell plate during cytokinesis. In the present study, we have identified tobacco NQK1/NtMEK1 and NRK1 as a MAPKK and a MAPK, respectively, downstream of NPK1. NQK1/NtMEK1 complements the mutation in the PBS2 MAPKK gene of yeast in a manner that depends on both NPK1 and its activator, NACK1, a kinesin-like protein. Active NPK1 and NQK1/NtMEK1 phosphorylate and activate NQK1/NtMEK1 and NRK1, respectively. Both NQK1/NtMEK1 and NRK1, as well as NPK1, are activated at the late M phase of the cell cycle in tobacco cells, and they are rapidly inactivated by depolymerization of phragmoplast microtubules. These results suggest the existence of a MAPK cascade that consists of NPK1, NQK1/NtMEK1, and NRK1 and functions in a pro

SUBMITTER: Soyano T 

PROVIDER: S-EPMC196038 | biostudies-literature | 2003 Apr

REPOSITORIES: biostudies-literature