Signaling properties and pharmacological analysis of two sulfakinin receptors from the red flour beetle, Tribolium castaneum.
Sulfakinin is an insect neuropeptide that constitutes an important component of the complex network of hormonal and neural factors that regulate feeding and digestion. The key modulating functions of sulfakinin are mediated by binding and signaling via G-protein coupled receptors. Although a substantial amount of functional data have already been reported on sulfakinins in different insect species, only little information is known regarding the properties of their respective receptors. In this study, we report on the molecular cloning, functional expression and characterization of two sulfakinin receptors in the red flour beetle, Tribolium castaneum. Both receptor open reading frames show extensive sequence similarity with annotated sulfakinin receptors from other insects. Comparison of the sulfakinin receptor sequences with homologous vertebrate cholecystokinin receptors reveals crucial conserved regions for ligand binding and receptor activation. Quantitative reverse transcriptase PCR shows that transcripts of both receptors are primarily expressed in the central nervous system of the beetle. Pharmacological characterization using 29 different peptide ligands clarified the essential requirements for efficient activation of these sulfakinin receptors. Analysis of the signaling pathway in multiple cell lines disclosed that the sulfakinin receptors of T. castaneum can stimulate both the Ca²⁺ and cyclic AMP second messenger pathways. This in depth characterization of two insect sulfakinin receptors may provide useful leads for the further development of receptor ligands with a potential applicability in pest control and crop protection.
Molecular Developmental Physiology and Signal Transduction, Department of Biology, KU Leuven, Leuven, Vlaams-Brabant, Belgium.
Sven
S
Zels
Molecular Developmental Physiology and Signal Transduction, Department of Biology, KU Leuven, Leuven, Vlaams-Brabant, Belgium.
Heleen
H
Verlinden
Molecular Developmental Physiology and Signal Transduction, Department of Biology, KU Leuven, Leuven, Vlaams-Brabant, Belgium.
Senne
S
Dillen
Molecular Developmental Physiology and Signal Transduction, Department of Biology, KU Leuven, Leuven, Vlaams-Brabant, Belgium.
Rut
R
Vleugels
Areawide Pest Management Research Unit, Southern Plains Agricultural Research Center, USDA, College Station, Texas, United States of America.
Ronald J
RJ
Nachman
Molecular Developmental Physiology and Signal Transduction, Department of Biology, KU Leuven, Leuven, Vlaams-Brabant, Belgium.
Jozef
J
Vanden Broeck
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D005433:Flour / Q000469:parasitology*; D057809:HEK293 Cells; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D015398:Signal Transduction; D014231:Tribolium / Q000378:metabolism*
D019476:Insect Proteins; D009479:Neuropeptides; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled