Molecular and functional characterization of the first tick CAP2b (periviscerokinin) receptor from Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).
The cDNA of the receptor for CAP(2b)/periviscerokinin (PVK) neuropeptides, designated Rhimi-CAP(2b)-R, was cloned from synganglia of tick Rhipicephalus (Boophilus) microplus. This receptor is the ortholog of the insect CAP(2b)/PVK receptor, as concluded from analyses of the predicted protein sequence, phylogenetics and functional expression. Expression analyses of synganglion, salivary gland, Malpighian tubule, and ovary revealed Rhimi-CAP(2b)-R transcripts. The expression in mammalian cells of the open reading frame of Rhimi-CAP(2b)-R cDNA fused with a hemagglutinin tag at the receptor N-terminus was confirmed by immunocytochemistry. In a calcium bioluminescence assay the recombinant receptor was activated by the tick Ixodes scapularis CAP(2b)/PVK and a PVK analog with EC₅₀s of 64 nM and 249 nM, respectively. Tick pyrokinins were not active. This is the first report on the functional characterization of the CAP(2b)/PVK receptor from any tick species which will now permit the discovery of the physiological roles of these neuropeptides in ticks, as neurohormones, neuromodulators and/or neurotransmitters.
Department of Entomology, Texas A&M University, College Station, TX 77843, USA.
Yunlong
Y
Yang
Prati
P
Bajracharya
Paula
P
Castillo
Ronald J
RJ
Nachman
Patricia V
PV
Pietrantonio
D000818:Animals; D005260:Female; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D048494:Rhipicephalus / Q000378:metabolism*
D009479:Neuropeptides; D043562:Receptors, G-Protein-Coupled; C093061:periviscerokinin; C079229:pyrokinin
Bioluminescence calcium assay; Cardioacceleratory peptide 2b (CAP(2b))/periviscerokinins (PVK); G protein-coupled receptor (GPCR); Pyrokinins (PK); Tick; qRT-PCR