A shotgun phosphoproteomics analysis of embryos in germinated maize seeds.
To better understand the role that reversible protein phosphorylation plays in seed germination, we initiated a phosphoproteomic investigation of embryos of germinated maize seeds. A total of 776 proteins including 39 kinases, 16 phosphatases, and 33 phosphoproteins containing 36 precise in vivo phosphorylation sites were identified. All the phosphorylation sites identified, with the exception of the phosphorylation site on HSP22, have not been reported previously (Lund et al. in J Biol Chem, 276, 29924-29929, 2001). Assayed with QRT-PCR, the transcripts of ten kinase genes were found to be dramatically up-regulated during seed germination and those of four phosphatase genes were up-regulated after germination, which indicated that reversible protein phosphorylation occurred and complex regulating networks were activated during this period. At least one-third of these phosphoproteins are key components involved in biological processes which relate to seed germination, such as DNA repair, gene transcription, RNA splicing and protein translation, suggesting that protein phosphorylation plays an important role in seed germination. As far as we know, this is the first phosphoproteomic study on a monocot and it will lay a solid foundation for further study of the molecular mechanisms of seed germination and seedling development.
Lu
Tian-Cong
TC
Education Ministry Key Laboratory of Forest Tree Genetic Improvement and Biotechnology, Northeast Forestry University, Harbin, People's Republic of China.
Meng
Ling-Bo
LB
Yang
Chuan-Ping
CP
Liu
Gui-Feng
GF
Liu
Guan-Jun
GJ
Ma
Wei
W
Wang
Bai-Chen
BC
D000595:Amino Acid Sequence; D015870:Gene Expression; D018525:Germination / Q000235:genetics*; D008969:Molecular Sequence Data; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics; D012639:Seeds / Q000254:growth & development / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D053719:Tandem Mass Spectrometry; D003313:Zea mays / Q000196:embryology* / Q000378:metabolism
D010940:Plant Proteins; D011494:Protein Kinases; D010744:Phosphoric Monoester Hydrolases