The function of ENSG00000154678 (PDE1C, phosphodiesterase 1C) is as follows. Calmodulin-dependent cyclic nucleotide phosphodiesterase with a dual specificity for the second messengers cAMP and cGMP, which are key regulators of many important physiological processes (PubMed:29860631, PubMed:8557689). Has a high affinity for both cAMP and cGMP (PubMed:8557689). Modulates the amplitude and duration of the cAMP signal in sensory cilia in response to odorant stimulation, hence contributing to the generation of action potentials. Regulates smooth muscle cell proliferation. Regulates the stability of growth factor receptors, including PDGFRB (Probable). In kidney juxtaglomerular granular cells, inhibits renin release by decreasing cAMP levels (By similarity). {ECO:0000250|UniProtKB:Q64338, ECO:0000269|PubMed:29860631, ECO:0000269|PubMed:8557689, ECO:0000305|PubMed:29860631}.