Table I. Phosphorylation changes in response to 5 min of osmotic stress

Phosphopeptides showing 2-fold or greater change in phosphorylation in response to 5 min of 0.3 m mannitol treatment and additional phosphopeptides selected for targeted proteomic analysis are shown. Phosphorylation sites that could not be localized to one residue are indicated by multiple residues inside brackets. MS/MS spectra for the listed phosphopeptides are documented in Supplemental Figure S1. n/a, Not applicable.

ATG Accession No.ProteinPhosphopeptideFold ChangeseTargeted MS Validation
Kinases/signaling related
 AT2G01690Vac14AT[pS]GVPFSQYK12.551.01Yes
 AT1G10940aSnRK2.1/4/5/10S[pT]VGTPAYIAPEVLSR6.182.06Yes
 AT1G53165MAP4Kα1SS[pS]ASEDSISNLAEAK4.870.72Yes
 AT1G16270MAP3K Raf18TV[pS]GGGIETEAR2.501.24Yes
Proteasome/ubiquitin related
 AT2G26590RPN13AGNLVVPNLSSEV[pS]DVTSSSGPVK3.840.23n/a
 AT2G47970NPL4 family proteinSIPGAPPVTPAG[pS]FGR2.290.18n/a
 AT3G63000NPL41 (NPL4-LIKE)GGPAVTPAG[pS]FGR2.060.09n/a
5′ mRNA decapping
 AT5G13570DCP2[pTS]VGGNGTATVESQNR4.480.04n/a
 AT3G13300VCS (varicose)TP[pS]ADYSVDR5.690.95Yes
ESITSAS[pS]VAQALSR5.502.01n/a
NLDVS[pS]VEEISR2.180.002n/a
TSGLPSQTSGAGSAYATLPQLPL[pS]PR0.490.06n/a
 AT3G13290VCR (varicose related)TS[pS]ADYFYVR3.980.53n/a
Cytoskeleton
 AT1G04820aTUA2/4/6TIQFVDWCP[pT]GFK2.800.30Yes
 AT5G19770aTUA1/3/5TVQFVDWCP[pT]GFK1.980.06Yes
 AT2G21380Kinase motor related[pSSS]TPTSTVYNSGGVTGSR2.530.93n/a
Channels/pumps
 AT3G58730Vacuolar ATPase D subunitGI[pS]INAAR2.910.66Yes
 AT5G60660Aquaporin PIP2FALGSFGSFG[pS]FR2.480.11Yes
ALGSFG[pS]FGSFR2.090.13No
 AT2G36380ATP-binding cassette transporter PDR6LP[pT]YDRLR2.490.78n/a
Vesicle trafficking related
 AT1G08800MyoB1ALLTQI[pS]ASR5.650.07Yes
 AT4G19490VPS54SI[pS]DASSQSLSSILNNPHGGK2.680.14n/a
 AT4G11740SAY1AASG[pS]LAPPNADR1.920.09Yes
 AT1G79830GC5QN[pS]AFENGSLPR2.780.004Yes
Metabolism related
 AT1G77120ADH1IIGVDFN[pS]K0.220.10No
 AT5G05600OxidoreductaseVQ[pS]LAESNLSSLPDR3.200.49No
 AT5G40390SIP1SD[pS]GINGVDFTEK1.510.06Yes
 AT3G58460RBL15[pTLS]TARDPTAPAGETDPNLHAR2.040.13n/a
Other/unknown
 AT2G21230bZIP30SI[pS]GEDTSDWSNLVK2.700.19Yes
 AT1G72410COP1-interacting relatedLSLGGG[pS]ADFSK4.730.26Yes
 AT3G03050Cellulose synthase-like CSLD3[pS]NLSTNSDAAEAER2.100.01n/a
 AT2G01190PB1 domain containingGF[pS]DSDTNVNR2.290.25Yes
 AT5G64430PB1 domain containingLFLFPASSGFG[pS]QSSTQSDRDR2.000.42n/a
 AT2G32240PICC defense responsiveDIDLSFS[pS]PTK1.490.001Yes
 AT5G56980A70 defense responsiveAP[pS]IIDR1.550.02Yes
 AT5G35430TPR domain containing[pTSS]LLSSSVASDTLR2.610.12n/a
 AT1G22060UnknownSVV[pS]GDLSGLAQSPQK2.370.54n/a
 AT5G58510UnknownTN[pS]VNQSPTDAIR2.100.01n/a
 AT5G42950GFY domain containing[pSPSS]DLLSILQGVTDR2.000.23n/a
  • a Peptide matches multiple family members.