title: Identification of VPA0451 as the specific chaperone for the Vibrio parahaemolyticus chromosome 1 type III-secreted effector VPA0450.
abstract: Vibrio parahaemolyticus is an important cause of gastroenteritis resulting from the consumption of raw or undercooked shellfish. The V. parahaemolyticus genome revealed the presence of two type III secretion systems (T3SS); one on each of the two chromosomes. To date, four effectors have been identified as secreted by the chromosome 1 T3SS (T3SS1). For some effectors, efficient secretion requires a cytosolic chaperone that is often encoded in close proximity to its cognate effector. In this study, we identified VPA0451 as the specific chaperone for the T3SS1 effector, VPA0450. VPA0451 is structurally similar to known T3SS chaperones. It is required for efficient VPA0450 secretion while not affecting the secretion of other T3SS1 effectors, suggesting it is a class 1A single cargo chaperone. VPA0450 translocation into the host cell membrane requires VPA0451. VPA0451 binds directly to VPA0450, and amino acids 25-100 contribute to this activity. Taken together, we conclude that VPA0451 is the cognate chaperone for the effector VPA0450 and is the second T3SS1 chaperone identified to date.
authors.affiliation: Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.
authors.forename: Barbara
authors.initials: B
authors.lastname: Waddell
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Southward
authors.forename: Neil
authors.initials: N
authors.lastname: McKenna
authors.forename: Rebekah
authors.initials: R
authors.lastname: Devinney
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D058947:Bacterial Secretion Systems; D001692:Biological Transport; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D018832:Molecular Chaperones / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D017384:Sequence Deletion; D014736:Vibrio parahaemolyticus / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; D010744:Phosphoric Monoester Hydrolases; C553203:VPA0450 protein, Vibrio parahaemolyticus
keywords: bacterial pathogenesis; bacterial secretion systems; food-borne illness; protein-protein interactions