Adenylyl cyclases (ACs) are a family of enzymes that synthesize cAMP, upon stimulation. cAMP is an important second messenger, which regulates carbohydrate, lipid, protein, and nucleic acid metabolism as well as synaptic transmission, ion channel function, and transcription in neurons¹. There are nine closely related isoforms of ACs (AC1–9) in mammals. All AC isoforms share a primary structure consisting of two hydrophobic regions which comprise six transmembrane helices and three large cytoplasmic domains. The basic catalytic unit of a membrane-bound AC molecule consists of the C1a and C2 domains. The N-terminus domains of ACs are highly variable, and might play a regulatory role².

Adenylyl cyclase type 3 (AC3) is widely expressed in the olfactory tissue, human cell line HEK-293, bovine brain, spinal cord, adrenal medulla, adrenal cortex, heart atrium, aorta, lung and retina³.

Several studies have suggested that AC3 may play an important role in the regulation of glucose metabolism and body weight. It was found that overexpression of AC3 mRNA is involved in pathophysiological metabolic processes, such as type 2 diabetes⁴. In addition, a recent study demonstrated the association of AC3 with gastric cancer as well as its tumorigenic potentials⁵.

Furthermore, AC3-knockout mice showed peripheral and behavioral anosmia⁶.