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:8557689, PubMed:29860631). 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). a nucleoside 3',5'-cyclic phosphate + H2O = a nucleoside 5'-phosphate + H(+) 3',5'-cyclic GMP + H2O = GMP + H(+) 3',5'-cyclic AMP + H2O = AMP + H(+) Binds 2 divalent metal cations per subunit. Site 1 may preferentially bind zinc ions. Binds 2 divalent metal cations per subunit. Site 2 has a preference for magnesium ions. Type I PDE are activated by the binding of calmodulin in the presence of Ca(2+). Homodimer. Isoform PDE1C2 is present in the heart and brain and, at lower levels in the lung, liver, kidney and skeletal muscle (PubMed:8557689). Isoform PDE1C1 is expressed in the heart and brain and, at lower levels in lung (PubMed:8557689). Also expressed at low levels in uterus and testis (PubMed:8557689). The disease is caused by variants affecting the gene represented in this entry. Belongs to the cyclic nucleotide phosphodiesterase family. PDE1 subfamily.