Identification, Functional Characterization, and Pharmacological Analysis of Two Sulfakinin Receptors in the...

Area of Science:

• * Insect physiology and neuroendocrinology
• * Molecular biology and receptor characterization

Background:

• * The sulfakinin (SK) signaling system is homologous to chordate gastrin/cholecystokinin systems.
• * SK signaling plays a role in regulating feeding behavior in various organisms.

Purpose of the Study:

• * To isolate and functionally characterize sulfakinin receptors (SKRs) in Rhodnius prolixus.
• * To elucidate the intracellular signaling pathways activated by Rhopr-SKRs.
• * To investigate the role of the SK-signaling pathway in the blood-feeding behavior of R. prolixus.

Main Methods:

• * Isolation of cDNA sequences for Rhopr-SKR-1 and Rhopr-SKR-2.
• * Functional receptor assays to determine ligand specificity and signaling pathways (Ca²⁺ and cAMP).
• * Spatial transcript expression analysis and gene knockdown experiments.

Main Results:

• * Identified two functional SKRs (Rhopr-SKR-1 and Rhopr-SKR-2) in R. prolixus, activated by native sulfakinins.
• * Rhopr-SKRs exclusively activate the intracellular Ca²⁺ pathway, not the cAMP pathway.
• * Knockdown of SK-signaling components increased blood meal intake, highlighting its role in satiation.

Conclusions:

• * The SK-signaling pathway is critical for regulating feeding behavior and satiation in R. prolixus.
• * Characterization of Rhopr-SKRs provides insights into blood meal coordination.
• * Understanding this pathway can inform strategies related to Chagas disease transmission.