A multicolor suite for deciphering population coding in calcium and cAMPin vivo

Abstract

cAMP is a pivotal second messenger regulated by various upstream pathways including Ca2+ and G protein-coupled receptors (GPCRs). To decipherin vivocAMP dynamics, we rationally designed cAMPinG1, an ultrasensitive genetically encoded green cAMP indicator that outperformed its predecessors in both dynamic range and cAMP affinity. Two-photon cAMPinG1 imaging detected cAMP transients in the somata and dendritic spines of neurons in the mouse visual cortex on the order of tens of seconds. In addition, multicolor imaging with a highly sensitive new red Ca2+ indicator RCaMP3 allowed simultaneous measurement of population patterns in Ca2+ and cAMP in hundreds of neurons. We identified Ca2+-induced cAMP responses that represented specific information, such as direction selectivity in vision and locomotion, as well as GPCR-induced cAMP responses. Overall, our multicolor suite revealed that information encoded in Ca2+ and GPCRs signaling is integrated and stored as cAMP transients for longer periodsin vivo.

Genome-wide CRISPR screen identifies AC9 as a key regulator of ER Ca2+homeostasis involved in neuronal differentiation

“…To investigate whether the regulation of ER Ca 2+ levels depends on the cAMP-PKA pathway, we employed various methods to elevate basal cytosolic cAMP levels and monitored the corresponding alterations in ER Ca 2+ levels. We utilized the recently-developed cAMP indicator, cAMPinG1, to monitor basal cAMP levels [29] . Specifically, cells treated with the ACs activator forskolin (FSK) at 0.5 μM showed an approximately 3-fold increase in resting cAMP levels, while 25 μM FSK resulted in an even greater increase of cAMP by approximately 8-fold.…”