Nitrophorin synthesis is modulated by protein kinase CK2.
Rhodnius prolixus is a blood-sucking bug whose saliva contains a family of nitric oxide-carrying proteins named nitrophorins (NPs). Saliva is injected into the host bloodstream during insect feeding. Nitric oxide is then released from NPs and will act on vascular smooth muscle, promoting vasodilation. Epithelial cells of salivary glands then undergo a massive synthesis of antihemostatics including NPs which produces saliva for the next blood meal. Here, we demonstrate the transient activation of a protein kinase in the salivary glands of R. prolixus after a blood meal. Biochemical, immunological, and pharmacological assays were used to identify this enzyme as protein kinase CK2. CK2 is activated after a blood meal and decreases to basal levels when salivary gland refilling is resumed. Inhibition of CK2 blocked [(35)S]methionine incorporation into newly synthesized salivary gland proteins in cultured tissue. Dissected salivary glands were then incubated with the heme fluorescent analog palladium (II) mesoporphyrin IX (Pd-MP) in the presence of a selective cell-permeable CK2 inhibitor, TBB (4,5,6,7-tetrabromobenzotriazole). NP synthesis was quantified based on fluorescence of the Pd-MP group bound to the NP heme pocket. TBB dramatically blocked NP synthesis. Altogether, these data are the first demonstration to show that antihemostatic synthesis in a blood-sucking arthropods is under protein phosphorylation control.
Mesquita
Rafael D
RD
Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, Brazil.
de Oliveira
Francisco Meirelles Bastos
FM
Shugar
David
D
Fantappié
Marcelo R
MR
Silva-Neto
Mário A C
MA
D000818:Animals; D015153:Blotting, Western; D047390:Casein Kinase II / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006420:Hemeproteins / Q000096:biosynthesis*; D010766:Phosphorylation; D012239:Rhodnius; D012469:Salivary Glands / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000096:biosynthesis*
D006420:Hemeproteins; D012471:Salivary Proteins and Peptides; C090560:nitrophorin; D047390:Casein Kinase II