Flagellar motor switch

The flagellar motor switches from one direction of rotation to the other either spontaneously or in response to signals received from the receptors or other mediators. The element that receives the signal and determines the probability of the motor to rotate in a certain direction is the switch. 

Khan, S., Zhao, R.B. and Reese, T.S. (1998). Architectural features of the Salmonella typhimurium flagellar motor switch revealed by disrupted C-rings. /, Struct. Biol. 122, 311-319. 

Shukla, D., Zhu, X.Y and Matsumura, P. (1998). Flagellar motor-switch binding face of CheY and the biochemical basis of suppression by CheY mutants that compensate for motor-switch defects in Flscherichia coli. J. Biol. Chem. 273, 23 993-23999. 

N.R. Francis, G.E. Sosinsky, D. Thomas, D.J. Derosier, Isolation, Characterization and Structure of Bacterial, Flagellar, Motors Containing the Switch Complex , J. Mol. Biol., 235, 1261 (1994)... 

In the absence of stimuli, halobacterial cells spontaneously switch the rotational sense of their flagellar bundle. The time course of the probability for spontaneous motor switching was calculated from frequency distributions and was shown to be independent of the rotational sense [22]. Switching occurs with a constant probability per unit of time except in the early phase immediately after a switching event. Kinetically, spontaneous switching... 

The flagella of bacteria such as . coli and Salmonella can rotate counterclockwise and clockwise (the direction of rotation defined for a flagellum viewed from its distal end towards the bacterial cell), and they can also pause [209,405, 407, 591,658]. A pause seems to result from a futile switching attempt from counterclockwise to clockwise [211]. Under non-stimulated conditions, the flagella rotate mostly counterclockwise with brief intermissions of clockwise rotation and pauses. The flagellar motors of other bacterial species may similarly have three functional states, or they may only have two states rotation in one direction and pausing (e.g., in K sphaeroides), or rotation in both directions without pausing (e.g., in Pseudomonas) (Table 1). 

In some species the outcome of CheY P interaction with the switch is different from the outcome of this interaction in . coli. In H. salinarium, for example, CheY P appears to increase the switching probability rather than the clockwise probability of the motor [610]. In S. meliloti, an interaction of CheY P with the flagellar motor appears to slow down the rotation [675] instead of changing its direction (the flagella of S. meliloti rotate only in one direction—Table 1). In B. subtilis, phosphorylation of CheY apparently decreases (rather than increases) the clockwise probability [248]. 

Barak, R., Welch, M., Yanovsky, A., Oosawa, K. and Eisenbach, M. (1992). Acetyladenylate or its derivative acetylates the chemotaxis protein CheY in vitro and increases its activity at the flagellar switch. Biochemistry 31,10099-10107. Barak, R. and Eisenbach, M. (1996). Regulation of interaction between signaling protein CheY and flagellar motor during bacterial chemotaxis. Curr. Top. Cell. Reg. 34, 137-158. 

Berry, R.M. (1993). Torque and switching in the bacterial flagellar motor. An electrostatic model. Biophys. J. 64, 961-973. 

Boles, B.R. and McCarter, L.L. (2000). Insertional inactivation of genes encoding components of the sodium-type flagellar motor and switch of Vibrio parahaemolyticus. J. Bacteriol. 182, 1035-1045. 

Dean, G.E., Aizawa, S.-I. and Macnab, R.M. (1983). jlaAII (motC, cheV) of Salmonella typhimurium is a structural gene involved in energization and switching of the flagellar motor. J. Bacteriol. 154, 84-91. 

Eisenbach, M., Wolf, A., Welch, M., Caplan, S.R., Lapidus, I.R., Macnab, R.M., Aloni, H. and Asher, O. (1990). Pausing, switching and speed fluctuation of bacterial flagellar motor and their relation to motility and chemotaxis./. Mol. Biol. 211, 551 3. 

Francis, N.R., Sosinsty, G.E., Thomas, D. and DeRosier, D.J. (1994). Isolation, characterization and structure of bacterial flagellar motors containing the switch complex. /. Mol. Biol. 235,1261-1270. 

Montrone, M., Fisenbach, M., Oesterhelt, D. and Marwan, W. (1998). Regulation of switching frequency and bias of the bacterial flagellar motor by GheY and fumarate./. Bacteriol. 180, 3375-3380. 

Sagi-Yosef, Y., Khan, S. and Esenbach, M. (2003). Binding of the chemotaxis response regulator CheY to isolated, intact switch complex of the bacterial flagellar motor lack of cooperativily. Submitted. 

Turner, L., Caplan, S.R. and Berg, H.C. (1996). Temperature-induced switching of the bacterial flagellar motor. Biophys. J. 71, 2227-2233. 

Welch, M., Oosawa, K., Aizawa, S.-I. and Eisenbach, M. (1994). Effects of phosphorylation, Mg, and conformation of the chemotaxis protein CheY on its binding to the flagellar switch protein FliM. Biochemistry 33, 10470-10476. Welch, M., Margolin, Y., Caplan, S.R. and Eisenbach, M. (1995). Rotational asymmetry of Escherichia coli flagellar motor in the presence of arsenate. Biochim. Biophys. Acta 1268, 81-87. 

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