• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of jbacterPermissionsJournals.ASM.orgJournalJB ArticleJournal InfoAuthorsReviewers
J Bacteriol. Jun 1995; 177(12): 3496–3503.
PMCID: PMC177054

Regulated underexpression and overexpression of the FliN protein of Escherichia coli and evidence for an interaction between FliN and FliM in the flagellar motor.


The FliN protein of Escherichia coli is essential for the assembly and function of flagella. Here, we report the effects of regulated underexpression and overexpression of FliN in a fliN null strain. Cells that lack the FliN protein do not make flagella. When FliN is underexpressed, cells produce relatively few flagella and those made are defective, rotating at subnormal, rapidly varying speeds. These results are similar to what was seen previously when the flagellar protein FliM was underexpressed and unlike what was seen when the motility proteins MotA and MotB were underexpressed. Overexpression of FliN impairs motility and flagellation, as has been reported previously for FliM, but when FliN and FliM are co-overexpressed, motility is much less impaired. This and additional evidence presented indicate that FliM and FliN are associated in the flagellar motor, in a structure distinct from the MotA/MotB torque generators. A recent study showed that FliN might be involved in the export of flagellar components during assembly (A. P. Vogler, M. Homma, V. M. Irikura, and R. M. Macnab, J. Bacteriol. 173:3564-3572, 1991). We show here that approximately 50 amino acid residues from the amino terminus of FliN are dispensable for function and that the remaining, essential part of FliN has sequence similarity to a part of Spa33, a protein that functions in transmembrane export in Shigella flexneri. Thus, FliN might function primarily in flagellar export, rather than in torque generation, as has sometimes been supposed.

Full Text

The Full Text of this article is available as a PDF (552K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Berg HC, Block SM. A miniature flow cell designed for rapid exchange of media under high-power microscope objectives. J Gen Microbiol. 1984 Nov;130(11):2915–2920. [PubMed]
  • Blair DF, Berg HC. Restoration of torque in defective flagellar motors. Science. 1988 Dec 23;242(4886):1678–1681. [PubMed]
  • Blair DF, Berg HC. The MotA protein of E. coli is a proton-conducting component of the flagellar motor. Cell. 1990 Feb 9;60(3):439–449. [PubMed]
  • Blair DF, Berg HC. Mutations in the MotA protein of Escherichia coli reveal domains critical for proton conduction. J Mol Biol. 1991 Oct 20;221(4):1433–1442. [PubMed]
  • Blair DF, Dutcher SK. Flagella in prokaryotes and lower eukaryotes. Curr Opin Genet Dev. 1992 Oct;2(5):756–767. [PubMed]
  • Blair DF, Kim DY, Berg HC. Mutant MotB proteins in Escherichia coli. J Bacteriol. 1991 Jul;173(13):4049–4055. [PMC free article] [PubMed]
  • Block SM, Berg HC. Successive incorporation of force-generating units in the bacterial rotary motor. Nature. 309(5967):470–472. [PubMed]
  • Chun SY, Parkinson JS. Bacterial motility: membrane topology of the Escherichia coli MotB protein. Science. 1988 Jan 15;239(4837):276–278. [PubMed]
  • Clegg DO, Koshland DE., Jr Identification of a bacterial sensing protein and effects of its elevated expression. J Bacteriol. 1985 Apr;162(1):398–405. [PMC free article] [PubMed]
  • De Mot R, Vanderleyden J. The C-terminal sequence conservation between OmpA-related outer membrane proteins and MotB suggests a common function in both gram-positive and gram-negative bacteria, possibly in the interaction of these domains with peptidoglycan. Mol Microbiol. 1994 Apr;12(2):333–334. [PubMed]
  • Dreyfus G, Williams AW, Kawagishi I, Macnab RM. Genetic and biochemical analysis of Salmonella typhimurium FliI, a flagellar protein related to the catalytic subunit of the F0F1 ATPase and to virulence proteins of mammalian and plant pathogens. J Bacteriol. 1993 May;175(10):3131–3138. [PMC free article] [PubMed]
  • Francis NR, Irikura VM, Yamaguchi S, DeRosier DJ, Macnab RM. Localization of the Salmonella typhimurium flagellar switch protein FliG to the cytoplasmic M-ring face of the basal body. Proc Natl Acad Sci U S A. 1992 Jul 15;89(14):6304–6308. [PMC free article] [PubMed]
  • Francis NR, Sosinsky GE, Thomas D, DeRosier DJ. Isolation, characterization and structure of bacterial flagellar motors containing the switch complex. J Mol Biol. 1994 Jan 28;235(4):1261–1270. [PubMed]
  • Garza AG, Harris-Haller LW, Stoebner RA, Manson MD. Motility protein interactions in the bacterial flagellar motor. Proc Natl Acad Sci U S A. 1995 Mar 14;92(6):1970–1974. [PMC free article] [PubMed]
  • Gill SC, von Hippel PH. Calculation of protein extinction coefficients from amino acid sequence data. Anal Biochem. 1989 Nov 1;182(2):319–326. [PubMed]
  • Hamilton CM, Aldea M, Washburn BK, Babitzke P, Kushner SR. New method for generating deletions and gene replacements in Escherichia coli. J Bacteriol. 1989 Sep;171(9):4617–4622. [PMC free article] [PubMed]
  • Hirota N, Imae Y. Na+-driven flagellar motors of an alkalophilic Bacillus strain YN-1. J Biol Chem. 1983 Sep 10;258(17):10577–10581. [PubMed]
  • Irikura VM, Kihara M, Yamaguchi S, Sockett H, Macnab RM. Salmonella typhimurium fliG and fliN mutations causing defects in assembly, rotation, and switching of the flagellar motor. J Bacteriol. 1993 Feb;175(3):802–810. [PMC free article] [PubMed]
  • Jones CJ, Aizawa S. The bacterial flagellum and flagellar motor: structure, assembly and function. Adv Microb Physiol. 1991;32:109–172. [PubMed]
  • Khan S, Dapice M, Reese TS. Effects of mot gene expression on the structure of the flagellar motor. J Mol Biol. 1988 Aug 5;202(3):575–584. [PubMed]
  • Larsen SH, Adler J, Gargus JJ, Hogg RW. Chemomechanical coupling without ATP: the source of energy for motility and chemotaxis in bacteria. Proc Natl Acad Sci U S A. 1974 Apr;71(4):1239–1243. [PMC free article] [PubMed]
  • Liu JD, Parkinson JS. Genetics and sequence analysis of the pcnB locus, an Escherichia coli gene involved in plasmid copy number control. J Bacteriol. 1989 Mar;171(3):1254–1261. [PMC free article] [PubMed]
  • Malakooti J, Komeda Y, Matsumura P. DNA sequence analysis, gene product identification, and localization of flagellar motor components of Escherichia coli. J Bacteriol. 1989 May;171(5):2728–2734. [PMC free article] [PubMed]
  • Oosawa K, Ueno T, Aizawa S. Overproduction of the bacterial flagellar switch proteins and their interactions with the MS ring complex in vitro. J Bacteriol. 1994 Jun;176(12):3683–3691. [PMC free article] [PubMed]
  • Parkinson JS, Parker SR, Talbert PB, Houts SE. Interactions between chemotaxis genes and flagellar genes in Escherichia coli. J Bacteriol. 1983 Jul;155(1):265–274. [PMC free article] [PubMed]
  • Sanger F, Nicklen S, Coulson AR. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. [PMC free article] [PubMed]
  • Sasakawa C, Komatsu K, Tobe T, Suzuki T, Yoshikawa M. Eight genes in region 5 that form an operon are essential for invasion of epithelial cells by Shigella flexneri 2a. J Bacteriol. 1993 Apr;175(8):2334–2346. [PMC free article] [PubMed]
  • Schuster SC, Khan S. The bacterial flagellar motor. Annu Rev Biophys Biomol Struct. 1994;23:509–539. [PubMed]
  • Shine J, Dalgarno L. The 3'-terminal sequence of Escherichia coli 16S ribosomal RNA: complementarity to nonsense triplets and ribosome binding sites. Proc Natl Acad Sci U S A. 1974 Apr;71(4):1342–1346. [PMC free article] [PubMed]
  • Sockett H, Yamaguchi S, Kihara M, Irikura VM, Macnab RM. Molecular analysis of the flagellar switch protein FliM of Salmonella typhimurium. J Bacteriol. 1992 Feb;174(3):793–806. [PMC free article] [PubMed]
  • Stolz B, Berg HC. Evidence for interactions between MotA and MotB, torque-generating elements of the flagellar motor of Escherichia coli. J Bacteriol. 1991 Nov;173(21):7033–7037. [PMC free article] [PubMed]
  • Studier FW, Moffatt BA. Use of bacteriophage T7 RNA polymerase to direct selective high-level expression of cloned genes. J Mol Biol. 1986 May 5;189(1):113–130. [PubMed]
  • Tang H, Blair DF. Regulated underexpression of the FliM protein of Escherichia coli and evidence for a location in the flagellar motor distinct from the MotA/MotB torque generators. J Bacteriol. 1995 Jun;177(12):3485–3495. [PMC free article] [PubMed]
  • Venkatesan MM, Buysse JM, Oaks EV. Surface presentation of Shigella flexneri invasion plasmid antigens requires the products of the spa locus. J Bacteriol. 1992 Mar;174(6):1990–2001. [PMC free article] [PubMed]
  • Vogler AP, Homma M, Irikura VM, Macnab RM. Salmonella typhimurium mutants defective in flagellar filament regrowth and sequence similarity of FliI to F0F1, vacuolar, and archaebacterial ATPase subunits. J Bacteriol. 1991 Jun;173(11):3564–3572. [PMC free article] [PubMed]
  • Wilson ML, Macnab RM. Co-overproduction and localization of the Escherichia coli motility proteins motA and motB. J Bacteriol. 1990 Jul;172(7):3932–3939. [PMC free article] [PubMed]
  • Yamaguchi S, Aizawa S, Kihara M, Isomura M, Jones CJ, Macnab RM. Genetic evidence for a switching and energy-transducing complex in the flagellar motor of Salmonella typhimurium. J Bacteriol. 1986 Dec;168(3):1172–1179. [PMC free article] [PubMed]
  • Yamaguchi S, Fujita H, Ishihara A, Aizawa S, Macnab RM. Subdivision of flagellar genes of Salmonella typhimurium into regions responsible for assembly, rotation, and switching. J Bacteriol. 1986 Apr;166(1):187–193. [PMC free article] [PubMed]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...