Analysis of CheY/CheYp-dependent feedback and of different coupling mechanisms. Orange and blue bars indicate the time intervals of stimulation with attractant orange or, respectively, repellent blue light. (A) CheY vs. CheYp dependency of the demethylation rates (top) analyzed in variations of Model 3: only CheY dependency can explain the cheY deletion phenotype, as observed in . Explanations of the scheme (bottom) see Text. (B) Feedback of stimulated transducers via CheY on the demethylation rates of unstimulated transducers. (C) In a wildtype version of the model (two methylation-efficient transducer populations) Halobacterium-type methanol release patterns and adapting CheYp levels (inset) are obtained. (D) Model 4 with methylation-deficiencies on the transducers mediating orange light responses, and normal methylation on transducers mediating blue light responses: adaptation of CheYp (inset) is defect and the Halobacterium-type methanol release is not obtained on stimulation of the methylation-deficient transducers. (E) R-TWA complexes are conformationally coupled (see also Figure 6) in Model 5. Adaptation of CheYp (inset) and methanol release is comparable to the wildtype as observed experimentally.