title: Stimulus-induced translocation of the protein kinase A catalytic subunit to the apical membrane in blowfly salivary glands.
abstract: Secretion in blowfly (Calliphora vicina) salivary glands is regulated by the neurohormone serotonin (5-HT), which activates the InsP(3)/Ca(2+) pathway and the cAMP/protein kinase A (PKA) pathway in the secretory cells. The latter signaling cascade induces the activation of a vacuolar H(+)-ATPase on the apical membrane. Here, we have determined the distribution of PKA by using antibodies against the PKA regulatory subunit-II (PKA-RII) and the PKA catalytic subunit (PKA-C) of Drosophila. PKA is present in high concentrations within the secretory cells. PKA-RII and PKA-C co-distribute in non-stimulated glands, being enriched in the basal portion of the secretory cells. Exposure to 8-CPT-cAMP or 5-HT induces the translocation of PKA-C to the apical membrane, whereas the PKA-RII distribution remains unchanged. The recruitment of PKA-C to the apical membrane corroborates our hypothesis that vacuolar H(+)-ATPase, which is enriched in this membrane domain, is a target protein for PKA.
authors.affiliation: Institut für Biochemie und Biologie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Voss
authors.forename: Ruth
authors.initials: R
authors.lastname: Schmidt
authors.forename: Bernd
authors.initials: B
authors.lastname: Walz
authors.forename: Otto
authors.initials: O
authors.lastname: Baumann