Highlights d SponGee is a genetically encoded cGMP scavenger d SponGee inhibits cGMP-dependent downstream pathways d SponGee enables cell-specific manipulation of cGMPdependent processes in vivo d Subcellular targeting confers cell compartment specificity to SponGee

Highlights d Development of SpiCee, a genetically encoded calcium scavenger d SpiCee inhibits calcium-dependent downstream pathways d SpiCee enables cell-specific manipulation of calciumdependent processes in vivo d Subcellular targeting confers cell compartment specificity to SpiCee

Highlights d Neighboring retinal ganglion cells cooperate to co-stabilize their axonal arbors d Axonal arbor co-stabilization involves cAMP signaling d cAMP independently controls axon co-stabilization and spontaneous activity