title: A common assembly module in injectisome and flagellar type III secretion sorting platforms.
abstract: Translocating proteins across the double membrane of Gram-negative bacteria, type III secretion systems (T3SS) occur in two evolutionarily related forms: injectisomes, delivering virulence factors into host cells, and the flagellar system, secreting the polymeric filament used for motility. While both systems share related elements of a cytoplasmic sorting platform that facilitates the hierarchical secretion of protein substrates, its assembly and regulation remain unclear. Here we describe a module mediating the assembly of the sorting platform in both secretion systems, and elucidate the structural basis for segregation of homologous components among these divergent T3SS subtypes sharing a common cytoplasmic milieu. These results provide a foundation for the subtype-specific assembly of T3SS sorting platforms and will support further mechanistic analysis and anti-virulence drug design.
authors.affiliation: 1] Laboratory of Structural Microbiology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA [2] Tri-Institutional Medical Scientist Training Program, Weill Cornell Medical College, 1300 York Avenue, New York, New York 10021, USA.
authors.forename: Ryan Q
authors.initials: RQ
authors.lastname: Notti
authors.affiliation: New York Structural Biology Center, 89 Convent Avenue, New York, New York 10027, USA.
authors.forename: Shibani
authors.initials: S
authors.lastname: Bhattacharya
authors.affiliation: Laboratory of Structural Microbiology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors.forename: Mirjana
authors.initials: M
authors.lastname: Lilic
authors.affiliation: Laboratory of Structural Microbiology, Rockefeller University, 1230 York Avenue, New York, New York 10065, USA.
authors.forename: C Erec
authors.initials: CE
authors.lastname: Stebbins
mesh_terms: D000595:Amino Acid Sequence; D005407:Flagella / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012486:Salmonella typhimurium; D000069296:Type III Secretion Systems / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D000069296:Type III Secretion Systems