Poster: Proteomics
Abs #
973: Isoprenylation proteomics of germinating Arabidopsis thaliana seeds
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Presenter: |
Wan, Lianglu , lianglu.wan@nrc.ca |
Authors | Wan, Lianglu (A) (B) Kermode, Allison R (B) Olson, Doug (A) Ambrose, Stephen J (A) Ross, Andrew R.S. (A) Cutler, Adrian J (A) Abrams, Suzanne R (A) | | Affiliations: |
(A): Plant Biotechnology Institute, National Research Council of Canada
(B): Department of Biological Sciences, Simon Fraser University
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Protein isoprenylation involves the attachment of an isoprenoid group (typically farnesol or geranylgeranol) to a cysteine residue of the C-terminal motif CAAX, XCXC or XXCC (where C is a cysteine, A is aliphatic amino acid, and X is any amino acid). Following isoprenylation the C-terminal amino acids may be processed, and the C-terminus methylated or palmilated. Protein isoprenylation has been implicated in protein-protein interactions, membrane localization, cell cycle and various signaling pathways. Since approx 30% of human tumors contain mutated RAS proteins, isoprenylation may be an excellent pharmacological target for cancer therapy. So far no true RAS or G-protein g-subunit homologues have been identified in plants. However, farnesylated proteins do occur in plants, and share similar structural and biochemical characteristics with those in animals and yeast. Such proteins are known to be involved in plant cell division, cell wall modification, cell cycle, ABA signaling and auxin signaling. In Arabidopsis there are about 100 proteins containing C-terminal motifs required for isoprenylation (Nambara E. and McCourt P., Curr. Opin. Plant Biol. 2: 388-92, 1999). As part of our PENCE project to elucidate hormonal control of seed dormancy and germination, we have combined 2-dimensional gel electrophoresis with immunoblotting to display isoprenylated proteins in germinating Arabidopsis seeds, and mass spectrometry (MS) to identify these proteins. Commercial Saccharomyces cerevisiae mating hormone a2 factor, a model farnesylated peptide, was used to optimize conditions for C-terminal analysis by post-source decay MALDI-TOF MS and Q/TOF MS/MS.
