Minimum protein oscillator based on multisite phosphorylation∕dephosphorylation.
The authors propose a novel minimum oscillator whereby a protein with multiple phosphorylation sites directly embedded in a negative feedback loop can exhibit oscillation. They demonstrate that if the fully phosphorylated substrate inhibits the first phosphorylation step in a cooperative manner, multisite substrates can exhibit oscillatory behaviour at the presence of a kinase and phosphatase. With a fixed number of sites, the non-linearity of the negative feedback and the substrate∕enzyme ratio must be above certain threshold values to generate undamped oscillation. There is an inverse relationship between the number of phosphorylation sites and the minimum non-linearity of the negative feedback required for oscillation; that is, the ultrasensitivity and time delay rooted in multisite phosphorylation compensate for the explicit non-linearity in the negative feedback. The period and amplitude of oscillation are mainly determined by the number of phosphorylation sites and the substrate∕enzyme ratio. The authors' results suggest that a multisite protein can be exploited for the construction of a synthetic protein oscillator featuring simplicity, robustness and tunability.
University of Michigan, Department of Chemical Engineering, Ann Arbor, USA.
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S
Marjan Varedi K
P J
PJ
Woolf
X N
XN
Lin
D025461:Feedback, Physiological; D008954:Models, Biological; D010744:Phosphoric Monoester Hydrolases; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism
D011506:Proteins; D010744:Phosphoric Monoester Hydrolases