Structural and functional differences between pheromonotropic and melanotropic PK/PBAN receptors

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• 作者：Aliza Hariton-Shalev ; Moran Shalev ; Noam Adir ; Edurad Belausov ; Miriam Altstein
• 关键词：CAPA-DH ; capa-gene-derived peptide ; DH ; diapause hormone ; ECL ; extra-cellular loop ; GPCR ; G-protein-coupled receptor ; ICL ; intra-cellular loop ; Np ; neuropeptide ; PI ; pre-immune serum ; PK/PBAN ; pyrokinin/pheromone biosynthesis-activating neuropeptide ; PK/P
• 刊名：Biochimica et Biophysica Acta (BBA)/General Subjects
• 出版年：2013
• 出版时间：November, 2013
• 年：2013
• 卷：1830
• 期：11
• 页码：5036-5048
• 全文大小：2134 K

文摘

Background

The pyrokinin/pheromone biosynthesis-activating neuropeptide (PK/PBAN) plays a major role in regulating a wide range of physiological processes in insects. The ubiquitous and multifunctional nature of the PK/PBAN peptide family raises many questions regarding the mechanisms by which these neuropeptides elicit their effects and the nature of the receptors that mediate their functions.

Methods

A sex pheromone gland receptor of the PK/PBAN family from Heliothis peltigera female moth and a Spodoptera littoralis larval receptor were cloned and stably expressed, and their structural models, electrostatic potentials and cellular functional properties were evaluated.

Results

Homology modeling indicated highly conserved amino-acid residues in appropriate structural positions as experimentally shown for class A G-protein coupled receptors. Structural differences could be proposed and electrostatic potentials of the two receptor models revealed net charge differences. Calcium mobilization assays demonstrated that both receptors were fully functional and could initiate extracellular calcium influx to start PK/PBAN signal transduction. Evaluation of the signaling response of both receptors to PBAN and diapause hormone (DH) revealed a highly sensitive, though differential response. Both receptors responded to PBAN whereas only Spl-PK/PBAN-R exhibited a high response toward DH.

Conclusions

The structural, electrostatic and cellular functional differences indicate that different PK/PBAN in vivo functions may be mediated by different PK/PBAN receptors and elicited by different peptide(s).

General significance

The results advance our understanding of the mode of action of the PK/PBAN family, and might help in exploring novel high-affinity receptor-specific antagonists that can serve as a basis for the development of new families of insect-control agents.