title: Global impact of Salmonella pathogenicity island 2-secreted effectors on the host phosphoproteome.
abstract: During the late stages of infection, Salmonella secretes numerous effectors through a type III secretion system that is encoded within Salmonella pathogenicity island 2 (SPI2). Despite the importance of SPI2 as a major virulence factor leading to the systemic spread of the bacteria and diseases, a global view of its effects on host responses is still lacking. Here, we measured global impacts of SPI2 effectors on the host phosphorylation and protein expression levels in RAW264.7 and in HeLa cells, as macrophage and nonphagocytic models of infection. We observe that SPI2 effectors differentially modulate the host phosphoproteome and cellular processes (e.g. protein trafficking, cytoskeletal regulation, and immune signaling) in a host cell-dependent manner. Our unbiased approach reveals the involvement of many previously unrecognized proteins, including E3 ligases (HERC4, RanBP2, and RAD18), kinases (CDK, SIK3, and WNK1), and histones (H2B1F, H4, and H15), in late stages of Salmonella infection. Furthermore, from this phosphoproteome analysis and other quantitative screens, we identified HSP27 as a direct in vitro and in vivo molecular target of the only type III secreted kinase, SteC. Using biochemical and cell biological assays, we demonstrate that SteC phosphorylates multiple sites in HSP27 and induces actin rearrangement through this protein. Together, these results provide a broader landscape of host players contributing to specific processes/pathways mediated by SPI2 effectors than was previously appreciated.
authors: Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors: Koshi
authors: K
authors: Imami
authors: Amit P
authors: AP
authors: Bhavsar
authors: Hongbing
authors: H
authors: Yu
authors: Nat F
authors: NF
authors: Brown
authors: Lindsay D
authors: LD
authors: Rogers
authors: B Brett
authors: BB
authors: Finlay
authors: Leonard J
authors: LJ
authors: Foster
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D005786:Gene Expression Regulation; D044404:Genomic Islands; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006367:HeLa Cells; D006360:Heat-Shock Proteins; D054884:Host-Pathogen Interactions; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000378:metabolism* / Q000382:microbiology; D051379:Mice; D018832:Molecular Chaperones; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D025941:Protein Interaction Mapping; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D020543:Proteome / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D012486:Salmonella typhimurium / Q000235:genetics* / Q000472:pathogenicity*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D010750:Phosphoproteins; D020543:Proteome; D037521:Virulence Factors; D011494:Protein Kinases; C526376:SteC protein, Salmonella typhimurium