title: A tyrosine phosphorylation switch controls the interaction between the transmembrane modulator protein Wzd and the tyrosine kinase Wze of Lactobacillus rhamnosus.
abstract: BACKGROUND
  One proposed mechanism for assembly of secreted heteropolysaccharides by many Gram positive bacteria relies on the coordinated action of a polymerization complex through reversible phosphorylation events. The role of the tyrosine protein kinase transmembrane modulator is, however, not well understood.
  
  
  RESULTS
  The protein sequences deduced from the wzb, wzd and wze genes from Lactobacillus rhamnosus ATCC 9595 and RW-9595 M contain motifs also found in corresponding proteins CpsB, CpsC and CpsD from Streptococcus pneumoniae D39 (serotype 2). Use of an anti-phosphotyrosine antibody demonstrated that both Wzd and Wze can be found in tyrosine phosphorylated form. When tyrosine 266 was mutated to phenylalanine, WzdY266F showed slightly less phosphorylated protein than those produced by using eight other tyrosine mutated Wzd genes, when expressed along with Wze and Wzb in Lactococcus lactis subsp. cremoris MG1363. In order to demonstrate the importance of ATP for the interactions among these proteins, native and fusion Wzb, Wzd and Wze proteins were expressed and purified from Escherichia coli cultures. The modulator protein, Wzd, binds with the phosphotyrosine kinase Wze, irrespective of its phosphorylation status. However, Wze attained a higher phosphorylation level after interacting with phosphorylated Wzd in the presence of 10 mM ATP. This highly phosphorylated Wze did not remain in close association with phosphorylated Wzd.
  
  
  CONCLUSIONS
  The Wze tyrosine kinase protein of Lactobacillus rhamnosus thus carries out tyrosine phosphorylation of Wzd in addition to auto- and trans- phosphorylation of the kinase itself.
authors.affiliation: STELA Dairy Research Centre, INAF, Université Laval, Québec, G1V 0A6, QC, Canada. hjkang@ibs.re.kr.|Present address: Academy of Immunology and Microbiology (AIM), Institute for Basic Science (IBS), Pohang, 790-784, Republic of Korea. hjkang@ibs.re.kr.
authors.forename: Hye-Ji
authors.initials: HJ
authors.lastname: Kang
authors.affiliation: CIRI-U1111 INSERM- UMR5308 CNRS-UCBL-ENSL, Université de Lyon, Université Lyon 1, 10 rue Dubois, bât. Lwoff, F-69622, Villeurbanne cedex, France. gilbert@biomserv.univ-lyon1.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Gilbert
authors.affiliation: STELA Dairy Research Centre, INAF, Université Laval, Québec, G1V 0A6, QC, Canada. fbadeaux@gmail.com.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Badeaux
authors.affiliation: CNRS, UMR5240, Unité microbiologie, adaptation et pathogénie, Villeurbanne, F-69622, France. jcadani@live.fr.
authors.forename: Danièle
authors.initials: D
authors.lastname: Atlan
authors.affiliation: STELA Dairy Research Centre, INAF, Université Laval, Québec, G1V 0A6, QC, Canada. gisele.lapointe@fsaa.ulaval.ca.
authors.forename: Gisèle
authors.initials: G
authors.lastname: LaPointe
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D052201:Lacticaseibacillus rhamnosus / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011499:Protein Processing, Post-Translational; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D011505:Protein-Tyrosine Kinases