Studies on the role of protein kinase A in humoral immune response of Galleria mellonella larvae.
Protein kinase A (PKA) activity was detected in the fat body of Galleria mellonella larvae by a non-radioactive method using a specific peptide substrate-kemptide. The enzyme activity was stimulated by cAMP and its analogues: BzcMP, 8-Chl-cAMP and 8-Br-cAMP in concentrations of 1-4muM. Cyclic GMP was not effective in PKA activation. A two-fold increase in PKA activity was detected in the fat body of G. mellonella LPS-challenged larvae. Selective, membrane-permeable PKA inhibitors, H89 and Rp-8-Br-cAMPS, inhibited protein kinase A activity in the fat body of G. mellonella larvae in vitro and in vivo. The inhibition of PKA activity in vivo was correlated with a considerable lowering of haemolymph antibacterial activity and a decrease in lysozyme content in the fat body of immune challenged larvae. The use of phospho-motif antibodies recognising PKA phosphorylation consensus site allowed identification of four potential PKA phosphorylation substrates of 79, 45, 40 and 36kDa in G. mellonella fat body.
Cytryńska
Małgorzata
M
Department of Invertebrate Immunology, Institute of Biology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland. cytryna@biotop.umcs.lublin.pl
Zdybicka-Barabas
Agnieszka
A
Jakubowicz
Teresa
T
D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000276:immunology*; D005216:Fat Body / Q000201:enzymology* / Q000276:immunology; D006458:Hemolymph / Q000276:immunology; D007814:Larva / Q000201:enzymology* / Q000276:immunology; D009036:Moths / Q000201:enzymology* / Q000276:immunology; D009113:Muramidase / Q000378:metabolism
D000900:Anti-Bacterial Agents; D017868:Cyclic AMP-Dependent Protein Kinases; D009113:Muramidase