title: Cell wall proteins in apoplastic fluids of Arabidopsis thaliana rosettes: identification by mass spectrometry and bioinformatics.
abstract: Weakly bound cell wall proteins of Arabidopsis thaliana were identified using a proteomic and bioinformatic approach. An efficient protocol of extraction based on vacuum-infiltration of the tissues was developed. Several salts and a chelating agent were compared for their ability to extract cell wall proteins without releasing cytoplasmic contaminants. Of the 93 proteins that were identified, a large proportion (60%) was released by calcium chloride. From bioinformatics analysis, it may be predicted that most of them (87 out of 93) had a signal peptide, whereas only six originated from the cytoplasm. Among the putative apoplastic proteins, a high proportion (67 out of 87) had a basic pI. Numerous glycoside hydrolases and proteins with interacting domains were identified, in agreement with the expected role of the extracellular matrix in polysaccharide metabolism and recognition phenomena. Ten proteinases were also found as well as six proteins with unknown functions. Comparison of the cell wall proteome of rosettes with the previously published cell wall proteome of cell suspension cultures showed a high level of cell specificity, especially for the different members of several large multigenic families.
authors.affiliation: UMR 5546 CNRS-Université Paul Sabatier, Pôle de Biotechnologie Végétale, F-31326 Castanet-tolosan, France.
authors.forename: Georges
authors.initials: G
authors.lastname: Boudart
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Jamet
authors.forename: Michel
authors.initials: M
authors.lastname: Rossignol
authors.forename: Claude
authors.initials: C
authors.lastname: Lafitte
authors.forename: Gisèle
authors.initials: G
authors.lastname: Borderies
authors.forename: Alain
authors.initials: A
authors.lastname: Jauneau
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Esquerré-Tugayé
authors.forename: Rafael
authors.initials: R
authors.lastname: Pont-Lezica
mesh_terms: D017360:Arabidopsis / Q000737:chemistry*; D002458:Cell Fractionation; D002473:Cell Wall / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry; D019295:Computational Biology; D015180:Electrophoresis, Gel, Two-Dimensional; D008353:Mannitol / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification; D021382:Protein Sorting Signals; D020543:Proteome / Q000032:analysis*; D012492:Salts / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D002614:Chelating Agents; D010940:Plant Proteins; D021382:Protein Sorting Signals; D020543:Proteome; D012492:Salts; D008353:Mannitol