title: Yersinia enterocolitica TyeA, an intracellular regulator of the type III machinery, is required for specific targeting of YopE, YopH, YopM, and YopN into the cytosol of eukaryotic cells.
abstract: Pathogenic Yersinia species employ type III machines to target effector Yops into the cytosol of eukaryotic cells. Yersinia tyeA mutants are thought to be defective in the targeting of YopE and YopH without affecting the injection of YopM, YopN, YopO, YopP, and YopT into the cytosol of eukaryotic cells. One model suggests that TyeA may form a tether between YopN (LcrE) and YopD on the bacterial surface, a structure that may translocate YopE and YopH across the plasma membrane of eukaryotic cells (M. Iriarte, M. P. Sory, A. Boland, A. P. Boyd, S. D. Mills, I. Lambermont, and G. R. Cornelis, EMBO J. 17:1907-1918, 1998). We have examined the injection of Yop proteins by tyeA mutant yersiniae with the digitonin fractionation technique. We find that tyeA mutant yersiniae not only secreted YopE, YopH, YopM, and YopN into the extracellular medium but also targeted these polypeptides into the cytosol of HeLa cells. Protease protection, cell fractionation, and affinity purification experiments suggest that TyeA is located intracellularly and binds to YopN or YopD. We propose a model whereby TyeA functions as a negative regulator of the type III targeting pathway in the cytoplasm of yersiniae, presumably by preventing the export of YopN.
authors.affiliation: Department of Microbiology and Immunology, University of California-Los Angeles School of Medicine, Los Angeles, CA 90095, USA.
authors.forename: L W
authors.initials: LW
authors.lastname: Cheng
authors.forename: O
authors.initials: O
authors.lastname: Schneewind
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D001692:Biological Transport; D020013:Calcium Signaling; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002451:Cell Compartmentation; D002458:Cell Fractionation; D003600:Cytosol / Q000382:microbiology; D005057:Eukaryotic Cells / Q000382:microbiology; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009154:Mutation; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D015008:Yersinia enterocolitica / Q000472:pathogenicity*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C112196:TyeA protein, Yersinia; C078910:YopD protein, Yersinia; C063239:yopE protein, Yersinia; C060772:yopM protein, Yersinia; C070015:YopN protein, Yersinia; D017027:Protein Tyrosine Phosphatases; C067571:yopH protein, Yersinia