Dissecting mitogen-activated protein kinase cascades involving arabidopsis MKK6

• Main Author: Zeng, Qingning
• Language: English
• Published: University of British Columbia 2011
• Online Access: http://hdl.handle.net/2429/31941

Mitogen-activated protein (MAP) kinase cascades act as critical components in the signalling pathways of all eukaryotic cells. They play a pivotal role in the transduction of extra- and intra-cellular stimuli and regulate cell growth, proliferation, differentiation and cell death, through sequential activation of MAP kinase kinase kinases (MAPKKKs), MAP kinase kinases (MKKs), and MAP kinases (MPKs). These three components form modules that control the phosphorylation of various substrates including transcription factors, enzymes, and cytoskeleton-associated proteins. In the Arabidopsis genome, over 60 MAPKKKs (AtMKKK), 10 MAPKKs (AtMKK), and 20 MAPKs (AtMPK) have been identified. The smaller number of AtMKKs suggests that diverse signals may converge and be integrated at the level of AtMKK. Among the ten AtMKKs, MKK6 has been proposed to play a role in regulating cytokinesis. However, little is known about the hierarchal phosphorylation system containing MKK6. In this Ph.D. project, I aimed to dissect the MAP kinase cascades involving MKK6 in Arabidopsis. I investigated potential targets of MKK6. Four MAP kinases were identified to interact with, and be phosphorylated by, MKK6, namely, MPK4, MPK6, MPK11, and MPK13. Among them, MPK13 is developmentally co-expressed with MKK6, and both MPK13 and MKK6 display high Promoter === Science, Faculty of === Botany, Department of === Graduate