title: Essential domain of receptor tyrosine phosphatase beta (RPTPbeta) for interaction with Helicobacter pylori vacuolating cytotoxin.
abstract: Helicobacter pylori produces a potent exotoxin, VacA, which causes progressive vacuolation as well as gastric injury. Although VacA was able to interact with two receptor-like protein tyrosine phosphatases, RPTPbeta and RPTPalpha, RPTPbeta was found to be responsible for gastric damage caused by VacA. To define the region of RPTPbeta involved in VacA binding, we made mutants of human cDNA RPTPbeta-B, a short receptor form of RPTPbeta. Immunoprecipitation experiments to assess VacA binding to RPTPbeta-B mutants indicated that five residues (QTTQP) at positions 747-751 of the extracellular domain of RPTPbeta-B (which is commonly retained in RPTPbeta-A, a long form of RPTPbeta) play a crucial role in its interaction with VacA, resulting in vacuolation as well as Git-1 phosphorylation. Transfected cells expressing deletion mutant Delta752, which lacks QTTQP, or the double point mutant Delta747 (T748A,T749A) had diminished vacuolation in response to VacA. Treatment of RPTPbeta-B and Delta747 (which have QTTQP at 747-751) with neuraminidase and O-glycosidase diminished their VacA binding, whereas chondroitinase ABC did not have an effect. No inhibitory effect of pleiotrophin, a natural RPTPbeta ligand, on VacA binding to RPTPbeta-B or Delta747 was observed, supporting the conclusion that the extracellular region of RPTPbeta-B responsible for VacA binding is different from that involved in binding pleiotrophin. These data define the region in the RPTPbeta extracellular domain critical for VacA binding, in particular the sequence QTTQP at positions 747-751 with crucial threonines at positions 748 and 749 and are consistent with a role for terminal sialic acids possibly because of threonine glycosylation.
authors.affiliation: Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523, Japan.
authors.forename: Kinnosuke
authors.initials: K
authors.lastname: Yahiro
authors.forename: Akihiro
authors.initials: A
authors.lastname: Wada
authors.forename: Eiki
authors.initials: E
authors.lastname: Yamasaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nakayama
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Nishi
authors.forename: Jyunzou
authors.initials: J
authors.lastname: Hisatsune
authors.forename: Naoko
authors.initials: N
authors.lastname: Morinaga
authors.forename: Jan
authors.initials: J
authors.lastname: Sap
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Noda
authors.forename: Joel
authors.initials: J
authors.lastname: Moss
authors.forename: Toshiya
authors.initials: T
authors.lastname: Hirayama
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D019765:Chondroitin ABC Lyase / Q000737:chemistry; D006224:Cricetinae; D016207:Cytokines / Q000737:chemistry; D045647:DNA Glycosylases / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D020690:GTPase-Activating Proteins; D017353:Gene Deletion; D006031:Glycosylation; D006801:Humans; D047468:Immunoprecipitation; D008024:Ligands; D051379:Mice; D018345:Mice, Knockout; D008957:Models, Genetic; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics; D009439:Neuraminidase / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000235:genetics; D012313:RNA / Q000737:chemistry; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012794:Sialic Acids / Q000737:chemistry; D015398:Signal Transduction; D013912:Threonine / Q000737:chemistry; D014162:Transfection
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D016207:Cytokines; D017931:DNA Primers; D018076:DNA, Complementary; D020690:GTPase-Activating Proteins; C120766:Git1 protein, mouse; D008024:Ligands; D009419:Nerve Tissue Proteins; D010455:Peptides; D010750:Phosphoproteins; D020033:Protein Isoforms; D012794:Sialic Acids; C074689:VacA protein, Helicobacter pylori; C066845:pleiotrophin; D013912:Threonine; D012313:RNA; C516895:PTPRZ1 protein, human; D017027:Protein Tyrosine Phosphatases; C516896:Ptprz1 protein, mouse; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5; D009439:Neuraminidase; D045647:DNA Glycosylases; D019765:Chondroitin ABC Lyase