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. Author manuscript; available in PMC: 2016 Jun 15.
Published in final edited form as: Dev Biol. 2015 Apr 11;402(2):146–161. doi: 10.1016/j.ydbio.2015.03.016

Figure 1.

Figure 1

Oscillatory circuit. Binding of cAMP to the surface receptor (CAR1) activates adenylyl cyclase (ACA) via RasGTP. It also inhibits the cAMP phosphodiesterase (RegA) by activating the MAP kinase (Erk2). Both of these pathways are inhibited when the activity of cAMP dependent protein kinase (PKA) increases. Coupled differential equations of the kinetics indicate that PKA activity and the concentration of cAMP will oscillate with a 6 minute periodicity. PKA also stimulates the transcription factor GataC to induce aggregation stage genes. CAR1 is a GPCR that stimulates both RasGEF and RasGAP which form an incoherent feedforward loop to regulate RasGTP (Laub and Loomis, 1998; Takeda et al., 2012).