title: An Interaction between the Inner Rod Protein YscI and the Needle Protein YscF Is Required to Assemble the Needle Structure of theYersiniaType Three Secretion System.
abstract: The type III secretion system is a highly conserved virulence mechanism that is widely distributed in Gram-negative bacteria. It has a syringe-like structure composed of a multi-ring basal body that spans the bacterial envelope and a projecting needle that delivers virulence effectors into host cells. Here, we showed that theYersiniainner rod protein YscI directly interacts with the needle protein YscF inside the bacterial cells and that this interaction depends on amino acid residues 83-102 in the carboxyl terminus of YscI. Alanine substitution of Trp-85 or Ser-86 abrogated the binding of YscI to YscF as well as needle assembly and the secretion of effectors (Yops) and the needle tip protein LcrV. However,yscInull mutants that weretrans-complemented with YscI mutants that bind YscF still assembled the needle and secreted Yops, demonstrating that a direct interaction between YscF and YscI is critical for these processes. Consistently, YscI mutants that did not bind YscF resulted in greatly decreased HeLa cell cytotoxicity. Together, these results show that YscI participates in needle assembly by directly interacting with YscF.
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Shi-Yang
authors.initials: SY
authors.lastname: Cao
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Wan-Bin
authors.initials: WB
authors.lastname: Liu
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Ya-Fang
authors.initials: YF
authors.lastname: Tan
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Hui-Ying
authors.initials: HY
authors.lastname: Yang
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Zhang
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Wang
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Wang
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Ya-Jun
authors.initials: YJ
authors.lastname: Song
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China ruifuyang@gmail.com.
authors.forename: Rui-Fu
authors.initials: RF
authors.lastname: Yang
authors.affiliation: From the State Key laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China zmduams@163.com.
authors.forename: Zong-Min
authors.initials: ZM
authors.lastname: Du
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D016923:Cell Death; D006367:HeLa Cells; D006801:Humans; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D000069296:Type III Secretion Systems / Q000096:biosynthesis* / Q000737:chemistry / Q000633:toxicity; D015010:Yersinia pestis / Q000737:chemistry* / Q000472:pathogenicity
chemical_list: D001426:Bacterial Proteins; D000069296:Type III Secretion Systems; C505708:YscF protein, Yersinia pestis
keywords: Western blotting; Yersinia pestis; bacterial pathogenesis; inner rod protein; needle assembly; needle protein; protein assembly; protein-protein interaction; type III secretion system (T3SS)