Molecular Characterization of the β2-like Octopamine Receptor of Helicoverpa armigera

Gujar, Nidhi; Nikte, Siddhanta V.; Joshi, Rakesh; Joshi, M. P.

doi:10.1007/s00232-021-00172-3

Cited by 9 publications

(10 citation statements)

References 34 publications

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“…All six OA receptors from R. padi had seven α‐helix transmembrane domains which were typical of GPCRs, which were important in the regulation of multiple insect physiological activities (Guo et al, 2021; Guo et al, 2021; Maqueira et al, 2005). The CWxP motif of three RpOctβRs in the TM6 contained the microswitch Pro, which served as a pivot for the movement of the TM6 during receptor activation (Chelikani et al, 2007; Gujar et al, 2021). In accordance with the multiple sequence alignment, the encoded protein of RpOctR‐like had longer TM6 compared with orthologs in other model insects.…”

Section: Discussionmentioning

confidence: 99%

Octopamine receptor genes are involved in the starvation response ofRhopalosiphum padi(Hemiptera: Aphididae)

Wang

Tang

Huang

et al. 2022

Insect Molecular Biology

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Insect octopamine (OA) receptors are G‐protein coupled receptors (GPCRs) that play essential roles in physiological and behavioural processes. However, there is little information about the function of OA receptors in the aphids' response to stress. From the genome sequence of Rhopalosiphum padi genome sequence, a cosmopolitan cereal pest, we identified six OA receptor genes RpOAMB, RpOctR, RpOctβ1R, RpOctβ2R, RpOctβ3R, RpOctR‐like with two, one, one, four, four, seven exons, respectively. All the OA receptors contain seven transmembrane domains, which were the signature of GPCRs. Our results showed that (1) the contents of OA increased significantly after food starvation, (2) the transcription levels of RpOAMB, RpOctR, RpOctβ2R and RpOctβ3R increased after starvation and were restored after re‐feeding, and (3) the expression levels of these four genes decreased significantly 48 h post‐injection of dsRNA that targeted the respective genes. Knockdown of RpOctR, RpOctβ2R or RpOctβ3R genes significantly increased aphid mortality under 24 h starvation conditions. Mortality of R. padi injected with dsRpOctR or dsRpOctβ2R was significantly higher than control under 48 h starvation treatments. This is the first report on the role of OA receptors in the starvation response of aphids. The current study provides knowledge for a better understanding the physiological roles of insect OA receptors.

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Section: Discussionmentioning

confidence: 99%

Octopamine receptor genes are involved in the starvation response ofRhopalosiphum padi(Hemiptera: Aphididae)

Wang

Tang

Huang

et al. 2022

Insect Molecular Biology

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Section: Discussionmentioning

confidence: 99%

“…Furthermore, specific amino acid residues likely involved in the binding of OA and TA with their respective receptors were identified. For each receptor, an aspartic acid in the TM III and two to three serine residues in the TM V are associated with the receptors ability to bind TA and OA (Braza et al, 2019; Gujar et al, 2021). However, a mutagenesis study performed on A. gambiae OA receptors showed that different residues localized in TM VI might also be involved in binding with TA and OA, revealing a possibly more complex mechanism (Kastner et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Octopamine and tyramine signaling inAedes aegypti:characterization, distribution and potential role in the Dengue vector development and physiology

Finetti

Paluzzi

Orchard

et al. 2022

Preprint

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In insects, the biogenic amines octopamine (OA) and tyramine (TA) are involved in controlling several physiological and behavioural processes. OA and TA act as neurotransmitters, neuromodulators or neurohormones, performing their functions by binding to specific receptors belonging to the G protein-coupled receptor (GPCR) superfamily. OA and TA along with their receptors are involved in reproduction, smell perception, metabolism, and homeostasis. Moreover, OA and TA receptors are targets for insecticides and antiparasitic agents, such as the formamidine Amitraz. In the dengue and yellow fever vector, Aedes aegypti, limited research has been previously reported on their OA or TA receptors. Here, we identify and characterize the OA and TA receptors in A. aegypti. Bioinformatic tools have been used to identify four OA and three TA receptors in the genome of A. aegypti. The seven receptors are expressed in all developmental stages of A. aegypti; however, their highest transcript abundance is observed in the adult compared to the larval stages. Among several adult A. aegypti tissues examined, including the central nervous system, antennae and rostrum, midgut, Malpighian tubules, ovaries, and testes, the type 2 TA receptor (TAR2) transcript is most abundant in the ovaries and the type 3 TA receptor (TAR3) is enriched in the Malpighian tubules, leading us to hypothesize putative roles for these receptors in reproduction and diuresis, respectively. Furthermore, a blood meal influenced OA and TA receptor transcript expression patterns in adult female tissues at several time points post blood meal, suggesting these receptors may play key physiological roles associated with feeding. To better understand OA and TA signaling in A. aegypti, the transcript expression profiles of key enzymes in their biosynthetic pathway, namely tyrosine decarboxylase (Tdc) and tyramine β-hydroxylase (Tβh), were examined in developmental stages, adult tissues, and brains from blood-fed females. These findings provide information for better understanding the physiological roles of OA, TA, and their receptors in A. aegypti, and additionally, may help in the development of novel strategies for the control of these human disease vectors.

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“…11,48,49 Moreover, sequence differences in the ICL3 region allow for specific clade differences in protein sequences through sequence alignment and phylogenetic studies of all insect OARs. 49,50 Previous structural and conformational dynamics studies of GPCRs indicated that the ICL3 serves a vital role in terms of overall protein dynamics. 51,52 According to the RMSF results, the ICL3 becomes more stable on the binding of amitraz, which might trigger the rearrangement of residues involved in the binding of G protein.…”

Section: The Binding Of Amitraz Reduces the Flexibility Of Oct⊎2rmentioning

confidence: 99%

Mechanism of enhanced sensitivity of mutated β‐adrenergic‐like octopamine receptor to amitraz in honeybee Apis mellifera: An insight from MD simulations

Bao

et al. 2022

Pest Management Science

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BACKGROUND: Amitraz is one of the critical acaricides/insecticides for effective control of pest infestation of Varroa destructor mite, a devastating parasite of Apis mellifera, because of its low toxicity to honeybees. Previous assays verified that a typical G protein-coupled receptor, ⊎-adrenergic-like octopamine receptor (Oct⊎2R), is the unique target of amitraz, but the honeybee Oct⊎2R resists to amitraz. However, the underlying molecular mechanism of the enhanced sensitivity or toxicity of amitraz to mutated honeybee Oct⊎2R E208V/I335T/I350V is not fully understood. Here, molecular dynamics simulations are employed to explore the implied mechanism of the enhanced sensitivity to amitraz in mutant honeybee Oct⊎2R. RESULTS: We found that amitraz binding stabilized the structure of Oct⊎2R, particularly the intracellular loop 3 associated with the Oct⊎2R signaling. Then, it was further demonstrated that both mutations and ligand binding resulted in a more rigid and compact amitraz binding site, as well as the outward movement of the transmembrane helix 6, which was a prerequisite for G protein coupling and activation. Moreover, mutations were found to promote the binding between Oct⊎2R and amitraz. Finally, community analysis illuminated that mutations and amitraz strengthened the residue-residue communication within the transmembrane domain, which might facilitate the allosteric signal propagation and activation of Oct⊎2R. CONCLUSION: Our results unveiled structural determinants of improved sensitivity in the Oct⊎2R-amitraz complex and may contribute to further structure-based drug design for safer and less toxic selective insecticides.

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Molecular Characterization of the β2-like Octopamine Receptor of Helicoverpa armigera

Cited by 9 publications

References 34 publications

Octopamine receptor genes are involved in the starvation response ofRhopalosiphum padi(Hemiptera: Aphididae)

Octopamine receptor genes are involved in the starvation response ofRhopalosiphum padi(Hemiptera: Aphididae)

Octopamine and tyramine signaling inAedes aegypti:characterization, distribution and potential role in the Dengue vector development and physiology

Mechanism of enhanced sensitivity of mutated β‐adrenergic‐like octopamine receptor to amitraz in honeybee Apis mellifera: An insight from MD simulations

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