title: Biochemical and phylogenetic analysis of CEBiP-like LysM domain-containing extracellular proteins in higher plants.
abstract: The chitin elicitor-binding protein (CEBiP) from rice was the first plant lysin motif (LysM) protein for which the biological and biochemical function had been established. It belongs to a plant-specific family of extracellular LysM proteins (LYMs) for which we analyzed the phylogeny. LYMs are present in vascular plants only, where an early gene duplication event might have resulted in two types which were retained in present day genomes. LYMs consist of a signal peptide, three consecutive LysMs, separated by cysteine pairs, and a C-terminal region without any known signature, whose length allows the distinction between the two types, and which may be followed by a glycosylphosphatidylinositol (GPI) anchor motif. We analyzed a representative of each type, MtLYM1 and MtLYM2, from Medicago truncatula at the biochemical level and with respect to their expression patterns and observed some similarities but also marked differences. MtLYM1 and MtLYM2 proved to be very different with regard to abundance and apparent molecular mass on SDS-PAGE. Both undergo several post-translational modifications, including N-glycosylation and the addition of a GPI anchor, which would position the proteins at the outer face of the plasma membrane. Only MtLYM2, but not MtLYM1, showed specific binding to biotinylated N-acetylchitooctaose in a manner similar to CEBiP, which belongs to the same type. We postulate that LYM2-type proteins likely function in the perception of chitin-related molecules, whereas possible functions of LYM1-type proteins remain to be elucidated.
authors.affiliation: Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales (LRSV), BP 42617, 31326 Castanet-Tolosan, France; CNRS, UMR 5546, BP 42617, 31326 Castanet-Tolosan, France. fliegmann@lrsv.ups-tlse.fr
authors.forename: Judith
authors.initials: J
authors.lastname: Fliegmann
authors.forename: Sandra
authors.initials: S
authors.lastname: Uhlenbroich
authors.forename: Tomonori
authors.initials: T
authors.lastname: Shinya
authors.forename: Yves
authors.initials: Y
authors.lastname: Martinez
authors.forename: Benoit
authors.initials: B
authors.lastname: Lefebvre
authors.forename: Naoto
authors.initials: N
authors.lastname: Shibuya
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Bono
mesh_terms: D020816:Amino Acid Motifs; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002686:Chitin / Q000378:metabolism*; D016384:Consensus Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D035264:Flowers / Q000378:metabolism; D058851:GPI-Linked Proteins; D015870:Gene Expression; D006031:Glycosylation; D046913:Medicago truncatula / Q000235:genetics* / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism*; D010802:Phylogeny; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D018547:Plant Stems / Q000378:metabolism; D010944:Plants / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D015003:Yeasts / Q000235:genetics / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D009844:Oligosaccharides; D010940:Plant Proteins; D002686:Chitin; C082723:N-acetylchitooctaose