Protein kinase A-dependent and -independent activation of the V-ATPase in Malpighian tubules of Aedes aegypti

Autor(en): Tiburcy, Felix 
Beyenbach, Klaus W.
Wieczorek, Helmut 
Stichwörter: Aedes aegypti; APICAL MEMBRANE; Biology; BLOWFLY SALIVARY-GLANDS; cAMP; DROSOPHILA-MELANOGASTER; EPITHELIAL TRANSPORT; FLUID SECRETION; INTRACELLULAR PH REGULATION; Life Sciences & Biomedicine - Other Topics; Malpighian tubule; PLASMA-MEMBRANE; protein kinase A; TOBACCO HORNWORM MIDGUT; V-ATPase activity; VACUOLAR H+-ATPASE; YELLOW-FEVER MOSQUITO
Erscheinungsdatum: 2013
Herausgeber: COMPANY OF BIOLOGISTS LTD
Journal: JOURNAL OF EXPERIMENTAL BIOLOGY
Volumen: 216
Ausgabe: 5
Startseite: 881
Seitenende: 891
Zusammenfassung: 
Transepithelial ion transport in insect Malpighian tubules is energized by an apical V-ATPase. In hematophagous insects, a blood meal during which the animal ingests huge amounts of salt and water stimulates transepithelial transport processes linked to V-ATPase activation, but how this is accomplished is still unclear. Here we report that membrane-permeant derivatives of cAMP increase the bafilomycin-sensitive ATPase activity in Malpighian tubules of Aedes aegypti twofold and activate ATP-dependent transport processes. In parallel, membrane association of the V-1 subunits C and D increases, consistent with the assembly of the holoenzyme. The protein kinase A inhibitor H-89 abolishes all cAMP-induced effects, consistent with protein kinase A (PKA) being involved in V-ATPase activation. Metabolic inhibition induced by KCN, azide and 2,4-dinitrophenol, respectively, also induces assembly of functional V-ATPases at the membrane without PKA involvement, indicating a phosphorylation-independent activation mechanism.
ISSN: 00220949
DOI: 10.1242/jeb.078360

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