The Yersinia tyrosine phosphatase YopH targets a novel adhesion-regulated signalling complex in macrophages.
The Yersinia protein tyrosine phosphatase (PTP) YopH is translocated into eukaryotic cells by a type III secretion system that requires bacterial-host cell contact. YopH is composed of two modular effector domains: a substrate-binding domain located in the N-terminal region (residues 1-130) and a PTP catalytic domain located in the C-terminal region (residues 206-468). Previous studies have shown that YopH selectively targets tyrosine-phosphorylated proteins of approximate molecular weight 120 kDa (p120) and 55 kDa (p55) in murine macrophages. It has been demonstrated that p120 actually represents two tyrosine-phosphorylated target proteins, Cas and Fyb. We used the substrate-binding domain of YopH to affinity purify tyrosine-phosphorylated target proteins from lysates of J774A.1 macrophages. Protein microsequencing identified p55 as murine SKAP-HOM. Direct interaction between SKAP-HOM and a catalytically inactive form of YopH was demonstrated in vitro and in macrophages. In addition, we obtained evidence that SKAP-HOM is tyrosine phosphorylated in response to macrophage cell adhesion and that it forms a signalling complex with Fyb. We suggest that dephosphorylation of SKAP-HOM and Fyb by YopH allows yersiniae to interfere with a novel adhesion-regulated signal transduction pathway in macrophages.
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Department of Molecular Genetics, and Microbiology, Center for Infectious Diseases, School of Medicine, State University of New York at Stony Brook, 11794, USA.
Marie-Cardine
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Schraven
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Bliska
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D000595:Amino Acid Sequence; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D015153:Blotting, Western; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D047908:Intracellular Signaling Peptides and Proteins; D008264:Macrophages / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology*; D051379:Mice; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D011485:Protein Binding; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction
D001425:Bacterial Outer Membrane Proteins; D015815:Cell Adhesion Molecules; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; C116431:src kinase associated phosphoprotein 2; D017027:Protein Tyrosine Phosphatases; C067571:yopH protein, Yersinia