Proper stem cell maintenance and organ formation in the Arabidopsis shoot meristem requires the activity of the CLAVATA loci (CLV1, CLV2, CLV3). Plants homozygous for mutations in any of the CLV loci accumulate massive numbers of stem cells as an apparent consequence of defects in organ formation. The CLV loci encode signal transduction components - CLV1 encodes a receptor kinase, CLV2 a receptor-like protein, and CLV3 a ligand. Our previous work has characterized inactive and active CLV1 protein complexes in vivo, and many of the components of these complexes, including a protein phosphatase and a Rho-related protein. We seek to determine the mechanisms of receptor activation, how signal is relayed across the plasma membrane, and how the cytoplasmic components interact with each other to produce a signal that modifies gene expression and cell fate. This understanding will not only be central to understanding meristem development, stem cell maintenance, and organ formation, but may also provide one paradigm for receptor-mediated signaling in plants. In addition, components and features of signaling common between plants and animals will also be elucidated, perhaps illuminating features of animal signaling as yet unidentified. This research proposal is designed to get us closer to these goals through genetic and biochemical studies of key aspects and components of CLV1 signaling. Phosphorylation sties in CLV1 will reveal how the kinase domain becomes activated, where effectors bind, and what role each effector plays in vivo. Inducible activation of CLV1 signaling may allow us to dissect the early activation events, as well as monitor the activation of downstream kinases as well as regulation of WUS. POL will provide us with a critical downstream position from which to identify the cytoplasmic and nuclear portion of the signal transduction cascade, with preliminary indications of a significant role for MAPKs. Finally, determining the role and interactions of the redundant receptor-kinases BAM1 and BAM2 may be central to getting at the mechanism of CLV1 activation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM062962-02
Application #
6621681
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Anderson, Richard A
Project Start
2002-02-01
Project End
2006-01-31
Budget Start
2003-02-01
Budget End
2004-01-31
Support Year
2
Fiscal Year
2003
Total Cost
$248,405
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Lee, Chunghee; Clark, Steven E (2015) A WUSCHEL-Independent Stem Cell Specification Pathway Is Repressed by PHB, PHV and CNA in Arabidopsis. PLoS One 10:e0126006
Gish, Lindsey A; Gagne, Jennifer M; Han, Linqu et al. (2013) WUSCHEL-responsive At5g65480 interacts with CLAVATA components in vitro and in transient expression. PLoS One 8:e66345
Guo, Yongfeng; Ni, Jun; Denver, Robert et al. (2011) Mechanisms of molecular mimicry of plant CLE peptide ligands by the parasitic nematode Globodera rostochiensis. Plant Physiol 157:476-84
Gish, Lindsey A; Clark, Steven E (2011) The RLK/Pelle family of kinases. Plant J 66:117-27
Gagne, Jennifer M; Clark, Steven E (2010) The Arabidopsis stem cell factor POLTERGEIST is membrane localized and phospholipid stimulated. Plant Cell 22:729-43
Guo, Yongfeng; Han, Linqu; Hymes, Matthew et al. (2010) CLAVATA2 forms a distinct CLE-binding receptor complex regulating Arabidopsis stem cell specification. Plant J 63:889-900
Gagne, Jennifer M; Gish, Lindsey A; Clark, Steven E (2010) The role of the acyl modification, palmitoylation, in Arabidopsis stem cell regulation. Plant Signal Behav 5:1048-51
Guo, Yongfeng; Clark, Steven E (2010) Membrane distributions of two ligand-binding receptor complexes in the CLAVATA pathway. Plant Signal Behav 5:1442-5
Song, Sang-Kee; Hofhuis, Hugo; Lee, Myeong Min et al. (2008) Key divisions in the early Arabidopsis embryo require POL and PLL1 phosphatases to establish the root stem cell organizer and vascular axis. Dev Cell 15:98-109
Deyoung, Brody J; Clark, Steven E (2008) BAM receptors regulate stem cell specification and organ development through complex interactions with CLAVATA signaling. Genetics 180:895-904

Showing the most recent 10 out of 19 publications