N-terminal residues of SipB are required for its surface localization on Salmonella enterica serovar Typhimurium

• Published in: Microbiology (Society for General Microbiology) Vol. 154; no. 1; pp. 207 - 216
• Main Authors: Kim, Hyeon Guk, Kim, Bae Hoon, Kim, Jin Seok, Eom, Jeong Seon, Bang, Iel-Soo, Bang, Seong Ho, Lee, In Soo, Park, Yong Keun
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-01-2008; Society for General Microbiology
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Blotting, Western; Cell Membrane - metabolism; Endopeptidase K - metabolism; Fundamental and applied biological sciences. Psychology; Membrane Proteins - genetics; Membrane Proteins - metabolism; Metabolism. Enzymes; Microbiology; Microscopy, Fluorescence; Protein Binding; Protein Interaction Domains and Motifs; Salmonella enterica; Salmonella typhimurium - chemistry; Salmonella typhimurium - genetics; Salmonella typhimurium - metabolism; Immunoblotting assay; Bacteria; Genetics; Biomembrane; Immunofluorescence; Localization; Salmonella typhimurium; Enterobacteriaceae
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2007/011528-0

1 Laboratory of Microbial Genetics, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea
2 Institute of Biotechnology, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea
3 Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwang ju 501-759, Republic of Korea
4 Department of Biological Science, Hanseo University, Seosan 356-706, Republic of Korea
5 Department of Microbiology, Hannam University, DaeJeon 300-791, Republic of Korea
Correspondence Yong Keun Park ykpark{at}korea.ac.kr
SipB, one of the invasion proteins encoded in Salmonella pathogenicity island 1 (SPI-1), is known to be secreted outside the cell, where it functions as a translocon by assembling into a host-cell plasma membrane-integral structure. Here, we confirmed that wild-type SipB could be localized to the bacterial outer membrane, and further showed that its localization was dependent on extracellular secretion, and was independent of the presence of the SipD protein. Proteinase K susceptibility and immunofluorescence assays indicated that SipB was not incorporated into the outer membrane, but rather was displayed on the bacterial surface. Finally, mutation studies revealed that the N-terminal 100–140 aa (especially amino acids 135–138) of SipB were required for its localization on the bacterial outer membrane.
Abbreviations: DOC, sodium deoxycholate; IFA, immunofluorescence assay; SPI-1, Salmonella pathogenicity island 1; T3SS, type III secretion system
These authors contributed equally to this work.