Publication Information
de la Fuente van Bentem et al., 2006
No external accession available
Abstract
Nucleic Acids Res. 2006 Jun 28;34(11):3267-78. doi: 10.1093/nar/gkl429. Print
2006.
Phosphoproteomics reveals extensive in vivo phosphorylation of Arabidopsis
proteins involved in RNA metabolism.
de la Fuente van Bentem S(1), Anrather D, Roitinger E, Djamei A, Hufnagl T,
Barta A, Csaszar E, Dohnal I, Lecourieux D, Hirt H.
Author information:
(1)Department of Plant Molecular Biology, Max F. Perutz Laboratories, University
of Vienna, Dr Bohr-Gasse 9, 1030 Vienna, Austria.
sergio.de.la.fuente.van.bentem@univie.ac.at
Most regulatory pathways are governed by the reversible phosphorylation of
proteins. Recent developments in mass spectrometry-based technology allow the
large-scale analysis of protein phosphorylation. Here, we show the application
of immobilized metal affinity chromatography to purify phosphopeptides from
Arabidopsis extracts. Phosphopeptide sequences were identified by liquid
chromatography-tandem mass spectrometry (LC-MS/MS/MS). A total of 79 unique
phosphorylation sites were determined in 22 phosphoproteins with a putative role
in RNA metabolism, including splicing of mRNAs. Among these phosphoproteins, 12
Ser/Arg-rich (SR) splicing factors were identified. A conserved phosphorylation
site was found in most of the phosphoproteins, including the SR proteins,
suggesting that these proteins are targeted by the same or a highly related
protein kinase. To test this hypothesis, Arabidopsis SR protein-specific kinase
4 (SRPK4) that was initially identified as an interactor of SR proteins was
tested for its ability to phosphorylate the SR protein RSp31. In vitro kinase
assays showed that all in vivo phosphorylation sites of RSp31 were targeted by
SRPK4. These data suggest that the plant mRNA splicing machinery is a major
target of phosphorylation and that a considerable number of proteins involved in
RNA metabolism may be targeted by SRPKs.
DOI: 10.1093/nar/gkl429
PMCID: PMC1904105
PMID: 16807317 [Indexed for MEDLINE]
