Gene Symbol: fliG
Description: flagellar motor switching and energizing component
Alias: ECK1937, JW1923, flaAII.2, flaBII
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Paul K, Nieto V, Carlquist W, Blair D, Harshey R. The c-di-GMP binding protein YcgR controls flagellar motor direction and speed to affect chemotaxis by a "backstop brake" mechanism. Mol Cell. 2010;38:128-39 pubmed publisher
    ..We demonstrate that YcgR interacts with the flagellar switch-complex proteins FliG and FliM, most strongly in the presence of c-di-GMP...
  2. Chun S, Parkinson J. Bacterial motility: membrane topology of the Escherichia coli MotB protein. Science. 1988;239:276-8 pubmed
    ..Protease treatment of MotB in spheroplasts confirmed this view. The simple transmembrane organization of MotB is difficult to reconcile with a role as a proton conductor. ..
  3. Minamino T, Yamaguchi S, Macnab R. Interaction between FliE and FlgB, a proximal rod component of the flagellar basal body of Salmonella. J Bacteriol. 2000;182:3029-36 pubmed
    ..We suggest that FliE subunits constitute a junction zone between the MS ring and the rod and also that the proximal rod structure consists of FlgB subunits. ..
  4. Yamaguchi S, Aizawa S, Kihara M, Isomura M, Jones C, Macnab R. Genetic evidence for a switching and energy-transducing complex in the flagellar motor of Salmonella typhimurium. J Bacteriol. 1986;168:1172-9 pubmed
    ..This switch complex is probably mounted to the base of the flagellar basal body and, via binding of the CheY and CheZ proteins, receives sensory information and uses it to control flagellar operation. ..
  5. Garza A, Biran R, Wohlschlegel J, Manson M. Mutations in motB suppressible by changes in stator or rotor components of the bacterial flagellar motor. J Mol Biol. 1996;258:270-85 pubmed
    Five proteins (MotA, MotB, FliG, FliM and FliN) may be involved in energizing flagellar rotation in Escherichia coli...
  6. Al Mamun A, Tominaga A, Enomoto M. Cloning and characterization of the region III flagellar operons of the four Shigella subgroups: genetic defects that cause loss of flagella of Shigella boydii and Shigella sonnei. J Bacteriol. 1997;179:4493-500 pubmed
    ..Three other strains also had the fliD deletion, and two of them had another deletion in the fliF-fliG-fliH region. The fliD deletion might be the primary cause of loss of flagella in S. sonnei...
  7. Zhou J, Sharp L, Tang H, Lloyd S, Billings S, Braun T, et al. Function of protonatable residues in the flagellar motor of Escherichia coli: a critical role for Asp 32 of MotB. J Bacteriol. 1998;180:2729-35 pubmed
    ..The proteins most closely involved in motor rotation are MotA, MotB, and FliG. MotA and MotB are transmembrane proteins that function in transmembrane proton conduction and that are believed to ..
  8. Lowder B, Duyvesteyn M, Blair D. FliG subunit arrangement in the flagellar rotor probed by targeted cross-linking. J Bacteriol. 2005;187:5640-7 pubmed
    b>FliG is a component of the switch complex on the rotor of the bacterial flagellum. Each flagellar motor contains about 25 FliG molecules...
  9. Blair D, Berg H. Mutations in the MotA protein of Escherichia coli reveal domains critical for proton conduction. J Mol Biol. 1991;221:1433-42 pubmed
    ..The clustering of the mutations provides independent support for the suggestion that MotA is a transmembrane proton channel and places significant constraints on models for the molecular mechanism of ion conduction. ..

More Information


  1. Khan S, Dapice M, Reese T. Effects of mot gene expression on the structure of the flagellar motor. J Mol Biol. 1988;202:575-84 pubmed
    ..The concomitant loss of the rings and motility is consistent with the ring particles having a central role in the flagellar motor. ..
  2. Bren A, Eisenbach M. The N terminus of the flagellar switch protein, FliM, is the binding domain for the chemotactic response regulator, CheY. J Mol Biol. 1998;278:507-14 pubmed
    ..These results indicate that the CheY-binding domain of FliM is located at the N terminus, within residues 1 to 16, and suggest that FliM monomers can form a complete site for CheY binding. ..
  3. Tang H, Braun T, Blair D. Motility protein complexes in the bacterial flagellar motor. J Mol Biol. 1996;261:209-21 pubmed
    ..These are MotA, MotB, FliG, FliM and FliN...
  4. Suzuki H, Yonekura K, Namba K. Structure of the rotor of the bacterial flagellar motor revealed by electron cryomicroscopy and single-particle image analysis. J Mol Biol. 2004;337:105-13 pubmed
    The FliF ring is the base for self-assembly of the bacterial flagellum and the FliF/FliG ring complex is the core of the rotor of the flagellar motor...
  5. Van Way S, Millas S, Lee A, Manson M. Rusty, jammed, and well-oiled hinges: Mutations affecting the interdomain region of FliG, a rotor element of the Escherichia coli flagellar motor. J Bacteriol. 2004;186:3173-81 pubmed
    The FliG protein is a central component of the bacterial flagellar motor. It is one of the first proteins added during assembly of the flagellar basal body, and there are 26 copies per motor...
  6. Paul K, Gonzalez Bonet G, Bilwes A, Crane B, Blair D. Architecture of the flagellar rotor. EMBO J. 2011;30:2962-71 pubmed publisher
    ..and switching of the bacterial flagellum depends on a large rotor-mounted protein assembly composed of the proteins FliG, FliM and FliN, with FliG most directly involved in rotation...
  7. Kim E, Panushka J, Meyer T, Ide N, Carlisle R, Baker S, et al. Biogenesis of the Flagellar Switch Complex in Escherichia coli: Formation of Sub-Complexes Independently of the Basal-Body MS-Ring. J Mol Biol. 2017;429:2353-2359 pubmed publisher
    ..in the flagellar motor of Escherichia coli is under the control of a complex on the rotor formed from the proteins FliG, FliM, and FliN. FliG lies at the top of the switch complex (i.e...
  8. Toker A, Macnab R. Distinct regions of bacterial flagellar switch protein FliM interact with FliG, FliN and CheY. J Mol Biol. 1997;273:623-34 pubmed
    The FliG, FliM, and FliN proteins of the bacterial flagellar motor are believed to interact with one another to form the switch complex, which in turn is thought to interact with one of the chemotaxis proteins, CheY...
  9. Komeda Y, Silverman M, Simon M. Genetic analysis of Escherichia coli K-12 region I flagellar mutants. J Bacteriol. 1977;131:801-8 pubmed
    ..The definition of region I fla genes and their transcriptional relationships were confirmed by genetic tests with hybrid A phage carrying fla genes in this region. ..
  10. Hauser R, Ceol A, Rajagopala S, Mosca R, Siszler G, Wermke N, et al. A second-generation protein-protein interaction network of Helicobacter pylori. Mol Cell Proteomics. 2014;13:1318-29 pubmed publisher
    ..coli of which one third turned out to be conserved in both species. ..
  11. Brown P, Terrazas M, Paul K, Blair D. Mutational analysis of the flagellar protein FliG: sites of interaction with FliM and implications for organization of the switch complex. J Bacteriol. 2007;189:305-12 pubmed
    ..In Escherichia coli and Salmonella, the complex contains about 26 copies of FliG, 34 copies of FliM, and more then 100 copies of FliN, together forming the basal body C ring...
  12. González Pedrajo B, Minamino T, Kihara M, Namba K. Interactions between C ring proteins and export apparatus components: a possible mechanism for facilitating type III protein export. Mol Microbiol. 2006;60:984-98 pubmed
    The flagellar switch proteins of Salmonella, FliG, FliM and FliN, participate in the switching of motor rotation, torque generation and flagellar assembly/export. FliN has been implicated in the flagellar export process...
  13. Brown P, Hill C, Blair D. Crystal structure of the middle and C-terminal domains of the flagellar rotor protein FliG. EMBO J. 2002;21:3225-34 pubmed publisher
    The FliG protein is essential for assembly, rotation and clockwise/counter-clockwise (CW/CCW) switching of the bacterial flagellum...
  14. Sosinsky G, Francis N, DeRosier D, Wall J, Simon M, Hainfeld J. Mass determination and estimation of subunit stoichiometry of the bacterial hook-basal body flagellar complex of Salmonella typhimurium by scanning transmission electron microscopy. Proc Natl Acad Sci U S A. 1992;89:4801-5 pubmed
    ..amp; Aizawa, S.-I. (1990) J. Mol. Biol. 212, 377-387] using quantitative gel electrophoresis. The results of Jones et al., together with ours, account for all proteins in the basal body to within approximately 5% (or 200 kDa). ..
  15. Yakushi T, Yang J, Fukuoka H, Homma M, Blair D. Roles of charged residues of rotor and stator in flagellar rotation: comparative study using H+-driven and Na+-driven motors in Escherichia coli. J Bacteriol. 2006;188:1466-72 pubmed
    ..to depend upon electrostatic interactions between charged residues of the stator protein MotA and the rotor protein FliG. These charged residues are conserved in the Na+-driven polar flagellum of Vibrio alginolyticus, but mutational ..
  16. Yamaguchi S, Fujita H, Ishihara A, Aizawa S, Macnab R. Subdivision of flagellar genes of Salmonella typhimurium into regions responsible for assembly, rotation, and switching. J Bacteriol. 1986;166:187-93 pubmed
    ..Our results suggest that within the corresponding gene products there are specialized subregions for flagellar structure, motor rotation, and control of the sense of rotation. ..
  17. Yorimitsu T, Mimaki A, Yakushi T, Homma M. The conserved charged residues of the C-terminal region of FliG, a rotor component of the Na+-driven flagellar motor. J Mol Biol. 2003;334:567-83 pubmed
    b>FliG is an essential component of the flagellar motor and functions in flagellar assembly, torque generation and regulation of the direction of flagellar rotation...
  18. Bartlett D, Matsumura P. Identification of Escherichia coli region III flagellar gene products and description of two new flagellar genes. J Bacteriol. 1984;160:577-85 pubmed
    ..Two additional genes were found at the flaB locus, and we subdivided the flaB gene into flaB1, flaBII, and flaBIII...
  19. Reid S, Leake M, Chandler J, Lo C, Armitage J, Berry R. The maximum number of torque-generating units in the flagellar motor of Escherichia coli is at least 11. Proc Natl Acad Sci U S A. 2006;103:8066-71 pubmed
    ..Speed increments at high numbers of units are smaller than those at low numbers, indicating that not all units in a fully induced motor are equivalent. ..
  20. Suzuki H, Yonekura K, Murata K, Hirai T, Oosawa K, Namba K. A structural feature in the central channel of the bacterial flagellar FliF ring complex is implicated in type III protein export. J Struct Biol. 1998;124:104-14 pubmed
    ..This suggests that a domain of FliF partially occupies the central channel to be involved in the export and gate mechanism, and the domain changes its conformation depending on the ionic strength. ..
  21. Gohara M, Kobayashi S, Abe Yoshizumi R, Nonoyama N, Kojima S, Asami Y, et al. Biophysical characterization of the C-terminal region of FliG, an essential rotor component of the Na+-driven flagellar motor. J Biochem. 2014;155:83-9 pubmed publisher
    ..The rotational force is generated by the interaction between the cytoplasmic regions of the rotor and the stator. FliG is directly involved in the torque generation of the rotor protein by its interaction...
  22. Leake M, Chandler J, Wadhams G, Bai F, Berry R, Armitage J. Stoichiometry and turnover in single, functioning membrane protein complexes. Nature. 2006;443:355-8 pubmed
    ..04 s(-1): the dwell time of a given stator in the motor is only approximately 0.5 min. This is the first direct measurement of the number and rapid turnover of protein subunits within a functioning molecular machine. ..
  23. Baker M, Hynson R, Ganuelas L, Mohammadi N, Liew C, Rey A, et al. Domain-swap polymerization drives the self-assembly of the bacterial flagellar motor. Nat Struct Mol Biol. 2016;23:197-203 pubmed publisher
    ..Here we demonstrate that Escherichia coli FliG, one of the earliest-assembling flagellar motor proteins, forms ordered ring structures via domain-swap ..
  24. Duke T, Le Novère N, Bray D. Conformational spread in a ring of proteins: a stochastic approach to allostery. J Mol Biol. 2001;308:541-53 pubmed
    ..Conformational spread appears to be a natural extension of the familiar mechanism of allostery: a physically realistic mechanism that should apply widely to many structures built from protein molecules. ..
  25. Katayama E, Shiraishi T, Oosawa K, Baba N, Aizawa S. Geometry of the flagellar motor in the cytoplasmic membrane of Salmonella typhimurium as determined by stereo-photogrammetry of quick-freeze deep-etch replica images. J Mol Biol. 1996;255:458-75 pubmed
    ..Various dimensions of the MS ring complex and the C ring projecting from the membrane were determined by digital stereo-photogrammetry, and a three-dimensional model of the total basal structure is presented. ..
  26. Zhou J, Fazzio R, Blair D. Membrane topology of the MotA protein of Escherichia coli. J Mol Biol. 1995;251:237-42 pubmed
    ..These experiments establish that the main features of the suggested model for MotA topology are correct, furnishing a basis for more detailed structure-function studies of the MotA/MotB proton channel...
  27. Garza A, Harris Haller L, Stoebner R, Manson M. Motility protein interactions in the bacterial flagellar motor. Proc Natl Acad Sci U S A. 1995;92:1970-4 pubmed
    Five proteins (MotA, MotB, FliG, FliM, and FliN) have been implicated in energizing flagellar rotation in Escherichia coli and Salmonella typhimurium...
  28. Rajagopala S, Hughes K, Uetz P. Benchmarking yeast two-hybrid systems using the interactions of bacterial motility proteins. Proteomics. 2009;9:5296-302 pubmed publisher
  29. Passmore S, Meas R, Marykwas D. Analysis of the FliM/FliG motor protein interaction by two-hybrid mutation suppression analysis. Microbiology. 2008;154:714-24 pubmed publisher
    The Escherichia coli motor proteins FliM and FliG physically interact, presumably to control one or more of the functions of the bacterial flagellum clockwise/counterclockwise (CW/CCW) switch...
  30. Saijo Hamano Y, Uchida N, Namba K, Oosawa K. In vitro characterization of FlgB, FlgC, FlgF, FlgG, and FliE, flagellar basal body proteins of Salmonella. J Mol Biol. 2004;339:423-35 pubmed
    ..These results together with other data indicate that all of the ten flagellar axial proteins share structural characteristics and folding dynamics in relation to the mechanism of their self-assembly into the flagellar axial structure. ..
  31. Paul K, Blair D. Organization of FliN subunits in the flagellar motor of Escherichia coli. J Bacteriol. 2006;188:2502-11 pubmed
    ..It is present in >100 copies per flagellum and together with FliM and FliG forms the switch complex that functions in flagellar assembly, rotation, and clockwise-counterclockwise switching...
  32. Marykwas D, Schmidt S, Berg H. Interacting components of the flagellar motor of Escherichia coli revealed by the two-hybrid system in yeast. J Mol Biol. 1996;256:564-76 pubmed
    ..Three motor proteins, FliG, FliM, and FliN, have been implicated in this process...
  33. Ridgway H, Silverman M, Simon M. Localization of proteins controlling motility and chemotaxis in Escherichia coli. J Bacteriol. 1977;132:657-65 pubmed
    ..Differences in the intracellular locations of the che and mot gene prodcuts presumably reflect the functional attributes of these components. ..
  34. Cohen Ben Lulu G, Francis N, Shimoni E, Noy D, Davidov Y, Prasad K, et al. The bacterial flagellar switch complex is getting more complex. EMBO J. 2008;27:1134-44 pubmed publisher
    ..evidence that FRD binds to preparations of isolated switch complexes, forms a 1:1 complex with the switch protein FliG, and that this interaction is required for both flagellar assembly and switching the direction of flagellar ..
  35. Manson M. How 34 pegs fit into 26 + 8 holes in the flagellar motor. J Bacteriol. 2007;189:291-3 pubmed
  36. Zhou J, Lloyd S, Blair D. Electrostatic interactions between rotor and stator in the bacterial flagellar motor. Proc Natl Acad Sci U S A. 1998;95:6436-41 pubmed
    ..Mutational studies of the rotor protein FliG and the stator protein MotA showed that both proteins contain charged residues essential for motor rotation...
  37. Grünenfelder B, Gehrig S, Jenal U. Role of the cytoplasmic C terminus of the FliF motor protein in flagellar assembly and rotation. J Bacteriol. 2003;185:1624-33 pubmed
    ..100 amino acids at the C terminus of FliF are exposed to the cytoplasm and, through the interaction with the FliG switch protein, a component of the flagellar C ring, are essential for the assembly of the motor...
  38. Braun T, Al Mawsawi L, Kojima S, Blair D. Arrangement of core membrane segments in the MotA/MotB proton-channel complex of Escherichia coli. Biochemistry. 2004;43:35-45 pubmed
  39. Jones C, Macnab R, Okino H, Aizawa S. Stoichiometric analysis of the flagellar hook-(basal-body) complex of Salmonella typhimurium. J Mol Biol. 1990;212:377-87 pubmed
    ..The ring stoichiometries are discussed in light of other information concerning flagellar structure and function. ..
  40. Komeda Y, Kutsukake K, Iino T. Definition of additional flagellar genes in Escherichia coli K12. Genetics. 1980;94:277-90 pubmed
    ..The flB gene was found to be part of an operon: flB-flaI in region II. In region III, a previously unidentified gene flbC was located between hag and flaN. ..
  41. Chalmeau J, Dagkessamanskaia A, Le Grimellec C, Francois J, Sternick J, Vieu C. Contribution to the elucidation of the structure of the bacterial flagellum nano-motor through AFM imaging of the M-Ring. Ultramicroscopy. 2009;109:845-53 pubmed publisher
    ..In this work, we are interested in the FliG proteins, identified as the key functional proteins of this nano-machine...
  42. Komeda Y. Fusions of flagellar operons to lactose genes on a mu lac bacteriophage. J Bacteriol. 1982;150:16-26 pubmed
    ..These results are discussed with respect to the possible assembly sequence of the fla gene products. ..
  43. Marykwas D, Berg H. A mutational analysis of the interaction between FliG and FliM, two components of the flagellar motor of Escherichia coli. J Bacteriol. 1996;178:1289-94 pubmed
    The motor that drives the flagellar filament of Escherichia coli contains three "switch" proteins (FliG, FliM, and FliN) that together determine the direction of rotation...
  44. Roman S, Frantz B, Matsumura P. Gene sequence, overproduction, purification and determination of the wild-type level of the Escherichia coli flagellar switch protein FliG. Gene. 1993;133:103-8 pubmed
    ..The switch is a complex apparatus composed of at least three proteins--FliG, FliM and FliN...
  45. Lloyd S, Tang H, Wang X, Billings S, Blair D. Torque generation in the flagellar motor of Escherichia coli: evidence of a direct role for FliG but not for FliM or FliN. J Bacteriol. 1996;178:223-31 pubmed
    Among the many proteins needed for assembly and function of bacterial flagella, FliG, FliM, and FliN have attracted special attention because mutant phenotypes suggest that they are needed not only for flagellar assembly but also for ..
  46. Thomas D, Morgan D, DeRosier D. Rotational symmetry of the C ring and a mechanism for the flagellar rotary motor. Proc Natl Acad Sci U S A. 1999;96:10134-9 pubmed
    b>FliG, FliM, and FliN, key proteins for torque generation, are located in two rings. The first protein is in the M ring and the last two are in the C ring...
  47. Kim E, Panushka J, Meyer T, Carlisle R, Baker S, Ide N, et al. Architecture of the Flagellar Switch Complex of Escherichia coli: Conformational Plasticity of FliG and Implications for Adaptive Remodeling. J Mol Biol. 2017;429:1305-1320 pubmed publisher
    ..of the complex that regulates the direction of flagellar rotation assume either ~34 or ~25 copies of the protein FliG. Support for ~34 came from crosslinking experiments identifying an intersubunit contact most consistent with that ..
  48. Macnab R. How bacteria assemble flagella. Annu Rev Microbiol. 2003;57:77-100 pubmed
    ..Exported substrates diffuse down a narrow channel in the growing structure and assemble at the distal end, often with the help of a capping structure. ..
  49. Garza A, Bronstein P, Valdez P, Harris Haller L, Manson M. Extragenic suppression of motA missense mutations of Escherichia coli. J Bacteriol. 1996;178:6116-22 pubmed
    ..Class II suppressors were point mutations in the chromosomal motB or fliG genes...
  50. Sowa Y, Rowe A, Leake M, Yakushi T, Homma M, Ishijima A, et al. Direct observation of steps in rotation of the bacterial flagellar motor. Nature. 2005;437:916-9 pubmed
    ..We observe 26 steps per revolution, which is consistent with the periodicity of the ring of FliG protein, the proposed site of torque generation on the rotor...
  51. Alon U, Camarena L, Surette M, Aguera y Arcas B, Liu Y, Leibler S, et al. Response regulator output in bacterial chemotaxis. EMBO J. 1998;17:4238-48 pubmed
    ..Thus the level of intracellular P-CheY can be estimated from behavior determinations: approximately 30% of the intracellular pool of CheY appears to be phosphorylated in fully adapted wild-type cells. ..
  52. Welch M, Oosawa K, Aizawa S, Eisenbach M. Phosphorylation-dependent binding of a signal molecule to the flagellar switch of bacteria. Proc Natl Acad Sci U S A. 1993;90:8787-91 pubmed
    ..counterclockwise and clockwise rotation are controlled by a "switch complex" composed of three proteins (FliG, FliM, and FliN) and located at the base of the flagellar motor. The mechanism of function of the switch is unknown...
  53. Sagi Y, Khan S, Eisenbach M. Binding of the chemotaxis response regulator CheY to the isolated, intact switch complex of the bacterial flagellar motor: lack of cooperativity. J Biol Chem. 2003;278:25867-71 pubmed
    ..To address this question, we purified the intact switch complex (constituting the switch proteins FliG, FliM, and FliN and the scaffolding protein FliF) in quantities sufficient for biochemical work and used it to ..