Publication Information
Nühse et al., 2007
No external accession available
Abstract
Plant J. 2007 Sep;51(5):931-40. doi: 10.1111/j.1365-313X.2007.03192.x. Epub 2007
Jul 25.
Quantitative phosphoproteomic analysis of plasma membrane proteins reveals
regulatory mechanisms of plant innate immune responses.
Nühse TS(1), Bottrill AR, Jones AM, Peck SC.
Author information:
(1)The Sainsbury Laboratory, Norwich Research Park, Colney Lane, Norwich, UK.
Advances in proteomic techniques have allowed the large-scale identification of
phosphorylation sites in complex protein samples, but new biological insight
requires an understanding of their in vivo dynamics. Here, we demonstrate the
use of a stable isotope-based quantitative approach for pathway discovery and
structure-function studies in Arabidopsis cells treated with the bacterial
elicitor flagellin. The quantitative comparison identifies individual sites on
plasma membrane (PM) proteins that undergo rapid phosphorylation or
dephosphorylation. The data reveal both divergent dynamics of different sites
within one protein and coordinated regulation of homologous sites in related
proteins, as found for the PM H(+)-ATPases AHA1, 2 and 3. Strongly
elicitor-responsive phosphorylation sites may reflect direct regulation of
protein activity. We confirm this prediction for RbohD, an NADPH oxidase that
mediates the rapid production of reactive oxygen species (ROS) in response to
elicitors and pathogens. Plant NADPH oxidases are structurally distinct from
their mammalian homologues, and regulation of the plant enzymes is poorly
understood. On RbohD, we found both unchanging and strongly induced
phosphorylation sites. By complementing an RbohD mutant plant with
non-phosphorylatable forms of RbohD, we show that only those sites that undergo
differential regulation are required for activation of the protein. These
experiments demonstrate the potential for use of quantitative phosphoproteomics
to determine regulatory mechanisms at the molecular level and provide new
insights into innate immune responses.
DOI: 10.1111/j.1365-313X.2007.03192.x
PMCID: PMC2156193
PMID: 17651370 [Indexed for MEDLINE]
