TY  - JOUR
A1  - Heindorff, Kristoffer
A1  - Blenau, Wolfgang
A1  - Walz, Bernd
A1  - Baumann, Otto
T1  - Characterization of a Ca2+/calmodulin-dependent AC1 adenylyl cyclase in a non-neuronal tissue, the blowfly salivary gland
JF  - Cell calcium
N2  - Crosstalk between intracellular signalling pathways is a functionally important and widespread phenomenon in cell physiology across phyla. In the salivary gland of the blowfly, serotonin induces fluid secretion via parallel activation of both the InsP(3)/Ca2+ and the cAMP/PKA signalling pathways, which interact on multiple levels. We have determined the molecular identity of a link between both pathways that mediates a Ca2+-dependent rise of intracellular cAMP. Whereas hydrolysis of cAMP via phosphodiesterases is largely independent of Ca2+, cAMP synthesis by adenylyl cyclases (AC) is potentiated in a Ca2+/calmodulin (Ca2+/CaM)-dependent manner. The existence of a Ca2+/CaM-dependent AC is supported by physiological data and a molecular approach. We have cloned Cv rutabaga cDNA, encoding the first blowfly AC, and confirmed its expression in the salivary gland via reverse transcription followed by polymerase chain reaction. The putative gene product of Cv rutabaga is a Ca2+/CaM-dependent type I AC and shows highest homology to Rutabaga from Drosophila. Thus, a Ca2+/CaM-dependent AC serves as a link between the InsP(3)/Ca2+ and the cAMP/PKA signalling pathways in the salivary gland of the blowfly and might be important for the amplification and optimization of the secretory response.
KW  - Adenylyl cyclase
KW  - Phosphodiesterase
KW  - Crosstalk
KW  - Ca2+
KW  - cAMP
KW  - Intracellular signalling
KW  - Salivary gland
KW  - Calliphora vicina
KW  - Rutabaga
Y1  - 2012
U6  - https://doi.org/10.1016/j.ceca.2012.04.016
SN  - 0143-4160
VL  - 52
IS  - 2
SP  - 103
EP  - 112
PB  - Churchill Livingstone
CY  - Edinburgh
ER  - 
TY  - JOUR
A1  - Fechner, Lennart
A1  - Baumann, Otto
A1  - Walz, Bernd
T1  - Activation of the cyclic AMP pathway promotes serotonin-induced Ca2+ oscillations in salivary glands of the blowfly Calliphora vicina
JF  - Cell calcium
N2  - Ca2+ and cAMP signalling pathways interact in a complex manner at multiple sites. This crosstalk fine-tunes the spatiotemporal patterns of Ca2+ and cAMP signals. In salivary glands of the blowfly Calliphora vicina fluid secretion is stimulated by serotonin (5-hydroxytryptamine, 5-HT) via activation of two different 5-HT receptors coupled to the InsP(3)/Ca2+ (Cv5-HT2 alpha) or the cAMP pathway (Cv5-HT7), respectively. We have shown recently in permeabilized gland cells that cAMP sensitizes InsP(3)-induced Ca2+ release to InsP(3). Here we study the effects of the CAMP signalling pathway on 5-HT-induced oscillations in transepithelial potential (TEP) and in intracellular [Ca2+]. We show: (1) Blocking the activation of the cAMP pathway by cinanserin suppresses the generation of TEP and Ca2+ oscillations, (2) application of 8-CPT-cAMP in the presence of cinanserin restores 5-HT-induced TEP and Ca2+ oscillations, (3) 8-CPT-cAMP sensitizes the InsP(3)/Ca2+ signalling pathway to 5-HT and the Cv5-HT2 alpha, receptor agonist 5-MeOT, (4) 8-CPT-cAMP induces Ca2+ oscillations in cells loaded with subthreshold concentrations of InsP(3), (5) inhibition of protein kinase A by H-89 abolishes 5-HT-induced TEP and Ca2+ spiking and mimics the effect of cinanserin. These results suggest that activation of the cyclic AMP pathway promotes the generation of 5-HT-induced Ca2+ oscillations in blowfly salivary glands.
KW  - Calcium
KW  - Ca2+
KW  - Calcium oscillations
KW  - cAMP
KW  - Signalling
KW  - Crosstalk
KW  - Salivary gland
KW  - Calliphora
KW  - Blowfly
KW  - Insect
Y1  - 2013
U6  - https://doi.org/10.1016/j.ceca.2012.10.004
SN  - 0143-4160
VL  - 53
IS  - 2
SP  - 94
EP  - 101
PB  - Churchill Livingstone
CY  - Edinburgh
ER  -