Fuss N, Mujagic S, Erber J, Wachten S, Baumann A. Biochemical properties of heterologously expressed and native adenylyl cyclases from the honeybee brain (Apis mellifera L.). Insect Biochem.Mol.Biol. 2010;40(8):573-580.Cyclic AMP is an important intracellular signaling molecule participating e.g. in sensory signal transduction, cardiac myocyte regulation, learning and memory. The formation of cAMP is catalyzed by adenylyl cyclases. A variety of factors can modulate the properties of these enzymes and lead to dynamic changes of the intracellular cAMP concentration. Here we determined the tissue distribution of a recently cloned adenylyl cyclase (AmAC3) in honeybee brain. The protein is present in all neuropils. Intensive immunoreactivity was found in parts of the proto- and deutocerebrum and in the suboesophageal ganglion. Biochemical and pharmacological properties of AmAC3 and of native adenylyl cyclases in subregions of the honeybee brain were examined. Values for half-maximal activation with NKH477 were in the low micromolar range with 10.2 mu M for AmAC3 and 3.6-8.1 mu M for native enzymes. Biosynthesis of cAMP was specifically blocked by P-site inhibitors. Adenylyl cyclases in antennal lobes and AmAC3 share the inhibitory profile with 2',5'dd3'ATP > 3'AMP > 2'deoxyadenosine. In addition to P-site inhibitors AmAC3 activity was impaired by Ca2+/calmodulin. The results suggest that AmAC3 is a likely candidate to fulfill an integrative role in sensory, motor and higher-order information processing in the honeybee brain. (C) 2010 Elsevier Ltd. All rights reserved
