Comparative phosphoproteomic analysis of microsomal fractions of Arabidopsis thaliana and Oryza sativa subjected to high salinity.
Plants respond to salt stress by initiating phosphorylation cascades in their cells. Many key phosphorylation events take place at membranes. Microsomal fractions from 400 mM salt-treated Arabidopsis suspension plants were isolated, followed by trypsin shaving, enrichment using Zirconium ion-charged or TiO(2) magnetic beads, and tandem mass spectrometry analyses for site mapping. A total of 27 phosphorylation sites from 20 Arabidopsis proteins including photosystem II reaction center protein H PsbH were identified. In addition to Arabidopsis, microsomal fractions from shoots of 200 mM salt-treated rice was carried out, followed by trypsin digestion using shaving or tube-gel, and enrichment using Zirconium ion-charged or TiO(2) magnetic beads. This yielded identification of 13 phosphorylation sites from 8 proteins including photosystem II reaction center protein H PsbH. Label-free quantitative analysis suggests that the phosphorylation sites of PsbH were regulated by salt stress in Arabidopsis and rice. Sequence alignment of PsbH phosphorylation sites indicates that Thr-2 and Thr-4 are evolutionarily conserved in plants. Four conserved phosphorylation motifs were predicted, and these suggest that a specific unknown kinase or phosphatase is involved in high-salt stress responses in plants.
Institute of Plant Biology, National Taiwan University, Taipei, Taiwan. ifchang@ntu.edu.tw
Ing-Feng
IF
Chang
Jue-Liang
JL
Hsu
Pang-Hung
PH
Hsu
Wei-An
WA
Sheng
Shiuan-Jeng
SJ
Lai
Cindy
C
Lee
Chun-Wei
CW
Chen
Jen-Chieh
JC
Hsu
Shu-Ying
SY
Wang
Lan-Yu
LY
Wang
Ching-Chuan
CC
Chen
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D018527:Hydroponics; D008565:Membrane Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D012275:Oryza / Q000187:drug effects / Q000378:metabolism*; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism; D010766:Phosphorylation; D045332:Photosystem II Protein Complex / Q000032:analysis / Q000378:metabolism; D010940:Plant Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D054712:Salinity; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological
D008565:Membrane Proteins; D010750:Phosphoproteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; C063224:photosystem II, psbH subunit; D012965:Sodium Chloride