title: Bacterial chemoreceptors of different length classes signal independently.
abstract: Bacterial chemoreceptors sense environmental stimuli and govern cell movement by transmitting the information to the flagellar motors. The highly conserved cytoplasmic domain of chemoreceptors consists in an alpha-helical hairpin that forms in the homodimer a coiled-coil four-helix bundle. Several classes of chemoreceptors that differ in the length of the coiled-coil structure were characterized. Many bacterial species code for chemoreceptors that belong to different classes, but how these receptors are organized and function in the same cell remains an open question. E. coli cells normally code for single class chemoreceptors that form extended arrays based on trimers of dimers interconnected by the coupling protein CheW and the kinase CheA. This structure promotes effective coupling between the different receptors in the modulation of the kinase activity. In this work, we engineered functional derivatives of the Tsr chemoreceptor of E. coli that mimic receptors whose cytoplasmic domain is longer by two heptads. We found that these long Tsr receptors did not efficiently mix with the native receptors and appeared to function independently. Our results suggest that the assembly of membrane-bound receptors of different specificities into mixed clusters is dictated by the length-class to which the receptors belong, ensuring cooperative function only between receptors of the same class.
authors.affiliation: Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Buenos Aires, Argentina.
authors.forename: M Karina
authors.initials: MK
authors.lastname: Herrera Seitz
authors.forename: Vered
authors.initials: V
authors.lastname: Frank
authors.forename: Diego A
authors.initials: DA
authors.lastname: Massazza
authors.forename: Ady
authors.initials: A
authors.lastname: Vaknin
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Studdert
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D015398:Signal Transduction; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C000607604:tsr protein, E coli; D000071677:Histidine Kinase; C000607608:cheA protein, E coli