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Title: CORRELATION BETWEEN CYTOPLASMIC DOMAIN SEQUENCE AND AUTOPHOSPHORYLATION AMONG ARABIDOPSIS LEUCINE-RICH REPEAT RECEPTOR-LIKE KINASES

Author
item HARDIN, SHANE - UNIVERSITY OF ILLINOIS
item DHUNDAYDHAM, MURALI - NC STATE UNIVERSITY
item CLOUSE, STEVEN - NC STATE UNIVERSITY
item Huber, Steven

Submitted to: American Society of Plant Biologists
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2006
Publication Date: 7/1/2006
Citation: Hardin, S., Dhundaydham, M., Clouse, S.D., Huber, S.C. 2006. Correlation between cytoplasmic domain sequence and autophosphorylation among arabidopsis leucine-rich repeat receptor-like kinases. American Society of Plant Biologists [abstract]. Paper no. P36018. Available: http://abstracts.aspb.org/pb2006/public/P36/P36018.html.

Interpretive Summary:

Technical Abstract: The leucine-rich repeat receptor-like kinases (LRR-RLKs) are implicated in signaling roles during plant growth, development and defense. A paradigm for receptor kinase activation involves dimerization and auto- or trans-phosphorylation within the cytoplasmic domain. Our goals are to identify intracellular domain phosphorylation sites and their effects on the activity and protein-protein interactions of the Arabidopsis LRR-RLKs. His- and/or FLAG-tagged versions of the cytoplasmic domains of many of these kinases have been expressed in E. coli. The LRR-RLKs can be sub-divided into "RD" and "non-RD" types based on a signature sequence motif amino-terminal to the kinase domain activation loop that is postulated to correlate with the requirement for activation loop phosphorylation. All of the RD-type kinases tested to date displayed strong autophosphorylation activity, while non-RD kinases that had CD- and LD-sequences displayed weak but measurable autophosphorylation, using ProQ-Diamond stain. In marked contrast, the non-RD type kinases did not autophosphorylate anywhere within the cytoplasmic domain suggesting the necessity for transphosphorylation during activation. Analysis of peptide kinase activities demonstrated that distinct substrate preferences existed even within the autophosphorylated RD-type receptor-like kinases, suggesting that different downstream proteins may be uniquely targeted by different members of the family. Numerous known and novel autophosphorylation sites have also been identified in several LRR-RLKs through a combination of immobilized metal chelate resin purification of tryptic phosphopeptides, and MALDI-ToF mass and native post-source decay spectrometry, and will be discussed.