title: Biochemical properties of heterologously expressed and native adenylyl cyclases from the honeybee brain (Apis mellifera L.).
abstract: 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 μM for AmAC3 and 3.6-8.1 μM 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 Ca(2+)/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.
authors.affiliation: Institut für Strukturbiologie and Biophysik 1, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Fuss
authors.forename: Samir
authors.initials: S
authors.lastname: Mujagic
authors.forename: Joachim
authors.initials: J
authors.lastname: Erber
authors.forename: Sebastian
authors.initials: S
authors.lastname: Wachten
authors.forename: Arnd
authors.initials: A
authors.lastname: Baumann
mesh_terms: D000262:Adenylyl Cyclases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000818:Animals; D001516:Bees / Q000201:enzymology* / Q000235:genetics; D001921:Brain / Q000201:enzymology; D002460:Cell Line; D004789:Enzyme Activation; D015870:Gene Expression; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D019581:Neuropil / Q000201:enzymology; D021381:Protein Transport
chemical_list: D019476:Insect Proteins; D000262:Adenylyl Cyclases