title: Temporal analysis of sucrose-induced phosphorylation changes in plasma membrane proteins of Arabidopsis.
abstract: Sucrose is the main product of photosynthesis and the most common transport form of carbon in plants. In addition, sucrose is a compound that serves as a signal affecting metabolic flux and development. Here we provide first results of externally induced phosphorylation changes of plasma membrane proteins in Arabidopsis. In an unbiased approach, seedlings were grown in liquid medium with sucrose and then depleted of carbon before sucrose was resupplied. Plasma membranes were purified, and phosphopeptides were enriched and subsequently analyzed quantitatively by mass spectrometry. In total, 67 phosphopeptides were identified, most of which were quantified over five time points of sucrose resupply. Among the identified phosphorylation sites, the well described phosphorylation site at the C terminus of plasma membrane H(+)-ATPases showed a relative increase in phosphorylation level in response to sucrose. This corresponded to a significant increase of proton pumping activity of plasma membrane vesicles from sucrose-supplied seedlings. A new phosphorylation site was identified in the plasma membrane H(+)-ATPase AHA1 and/or AHA2. This phosphorylation site was shown to be crucial for ATPase activity and overrode regulation via the well known C-terminal phosphorylation site. Novel phosphorylation sites were identified for both receptor kinases and cytosolic kinases that showed rapid increases in relative intensities after short times of sucrose treatment. Seven response classes were identified including non-responsive, rapid increase (within 3 min), slow increase, and rapid decrease. Relative quantification of phosphorylation changes by phosphoproteomics provides a means for identification of fast responses to external stimuli in plants as a basis for further functional characterization.
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Golm, Germany.
authors.forename: Totte
authors.initials: T
authors.lastname: Niittylä
authors.forename: Anja T
authors.initials: AT
authors.lastname: Fuglsang
authors.forename: Michael G
authors.initials: MG
authors.lastname: Palmgren
authors.forename: Wolf B
authors.initials: WB
authors.lastname: Frommer
authors.forename: Waltraud X
authors.initials: WX
authors.lastname: Schulze
mesh_terms: D000595:Amino Acid Sequence; D020346:Aquaporins / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D016000:Cluster Analysis; D013058:Mass Spectrometry; D026901:Membrane Transport Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010748:Phosphopeptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010940:Plant Proteins / Q000378:metabolism; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D013379:Substrate Specificity / Q000187:drug effects; D013395:Sucrose / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D020346:Aquaporins; D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; D010748:Phosphopeptides; D010940:Plant Proteins; C078729:sucrose transport protein, plant; D013395:Sucrose; D011494:Protein Kinases; D006180:Proton-Translocating ATPases; D053499:Plasma Membrane Calcium-Transporting ATPases