Poster: Intracellular Signaling

Abs # 848: Functional analyses of MAPKs in Arabidopsis development

Presenter:	Mockaitis, Keithanne , mockaitis@bio.indiana.edu
Authors	Mockaitis, Keithanne  (A)   Alonso, José M. (B)   Stepanova, Anna N. (B)   Leisse, Thomas J. (B)   Chen, Huaming  (B)   Shinn, Paul  (B)   Kim, Christopher J. (B)   Zimmerman, Justin  (B)   Cheuk, Rosa  (B)   Karnes, Meagan  (B)   Carter, David  (C)   Marchantd, Trudy  (C)   Risseeuw, Eddy  (C)   Zeko, Albana  (C)   Crosby, William  (C)   Ecker, Joseph R. (B)   Estelle, Mark  (A)
Affiliations:	(A): Department of Biology and Indiana Molecular Biology Institute, Indiana University, Bloomington IN (B): Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla CA (C): NRC Plant Biotechnology Institute, Saskatoon, Canada

Mitogen activated protein kinase (MAPK) pathways modulate programs of environmental adaptation as well as cell proliferation, embryo development and organogenesis. Pathogen and hormone signals are transduced in part by the rapid action of these pathways (Frye et al., 2000; Petersen et al., 2000; and others), yet few of the ~80 genes that encode the protein kinases of MAPK cascades have been functionally examined in Arabidopsis. Presented here will be progress toward understanding MAPK signaling in Arabidopsis seedling development through the characterization of null mutants of the twenty MPK genes. MPKs encode the MAPK family members of Arabidopsis (Mizoguchi et al., 1993; Arabidopsis Genome Initiative 2000). These highly conserved protein kinases are activated at the final level of a three-member phosphorylation chain in all eukaryotes, initiating changes in the cellular program. Knock-out mutants in each MPK were obtained by screening of the Salk T-DNA insertion mutants. We have focused primarily on alterations in root development in these lines, in order to examine functions of auxin-induced MAPK activation previously observed in roots (Mockaitis and Howell, 2000) and to determine roles rapid protein kinase signaling may have in the context of components known to be essential for auxin response (Hellmann and Estelle, 2002).