Fig. 1: Negative and positive feedback driven oscillatory networks. | npj Systems Biology and Applications

Fig. 1: Negative and positive feedback driven oscillatory networks.

From: Systematic analysis of negative and positive feedback loops for robustness and temperature compensation in circadian rhythms

Fig. 1

Schematic diagram of Rust’s cyanobacterial oscillatory network in KaiABC (cyano-KaiABC) which operates through several positive feedback loops (a); Goodwin’s negative feedback loop operating between two species (Two-Variable-Goodwin-NFB) (b); a single molecule with combined positive and negative feedback that moves through four chemically modified states while interacting with an external molecule having two states (A and B) (cPNFB) (c) and Selkov’s substrate depletion oscillatory network, which is the simplest positive feedback loop and substrate depletion driven oscillator (Selkov-PFB) (d). activation/phosphorylation and inhibition/dephosphorylation reactions are represented by the green and red arrows, respectively. Inhibition processes are shown by blunt-headed arrows, whereas activation processes are represented by pointed-headed arrows. The reversible reactions are denoted by the double arrows in both directions. The direct reactions (synthesis/degradation, phosphorylation/dephosphorylation) are represented with solid arrows whereas the regulatory indirect reactions (activation/inhibition) are represented by the dashed arrows. Blue shaded parameters are fixed in models reported in Fig. 4 and yellow shaded ones are further fixed in the analysis at Fig. 5.

Back to article page