Skip to main content
. Author manuscript; available in PMC: 2018 Dec 31.
Published in final edited form as: ACS Synth Biol. 2018 Jun 4;7(6):1488–1495. doi: 10.1021/acssynbio.8b00065

Figure 4. Opto-RGS2 inhibitory feedback reduces stochasticity of calcium oscillation spike timing.

Figure 4.

(a) Interspike intervals of ligand-induced oscillations become less stochastic with feedback. (b) The negative feedback regulator and its coupling mechanism to global elevations in calcium are still unknown as reflected in the lump circuit diagram. (c) Proposed RGS2-mediated negative feedback loop, where inhibition of Gαq-signaling is coupled to global calcium elevations through relief of PIP3 inhibition of RGS2 by calcium-activated calmodulin (CaM). (d) Stochasticity (α) of 100 uM CCh-induced calcium oscillations in non-illuminated opto-RGS2 cell lines. (e) Opto-RGS2 activation decreased the stochasticity in response to a single blue light epoch (as in Figure 3). (f) The Inhibitory feedback is uncoupled from the global calcium elevation by CaM-antagonism by CALP2 peptide. (g) Statistical bootstrapping or resampling analysis of variance (N = 1000 trials) for panels d-f.