cADDis(Red-Up) is a genetically encoded fluorescent cAMP sensor. It is a fusion protein in which a circularly permuted red fluorescent protein is inserted in the hinge region of the Homo sapiens RAPGEF4 gene (HGNC:16626), in between the catalytic and enzymatic domains. Upon cAMP binding, RAPGEF4 changes conformation, resulting in an increase in fluorescence levels (PMID:26657040).