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Katali OKH, Marco HG, Gäde G. Structure-Activity Studies on the Hypertrehalosemic Hormone II of the Stick Insect Carausius morosus (Phasmatodea): Carbohydrate-Mobilization and Cardio-Stimulatory Activities. Front Physiol 2020; 11:315. [PMID: 32411004 PMCID: PMC7198766 DOI: 10.3389/fphys.2020.00315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/20/2020] [Indexed: 12/19/2022] Open
Abstract
The corpora cardiaca of the Indian stick insect, Carausius morosus, synthesize two decapeptide neuropeptides of the adipokinetic hormone (AKH) family, both of which can increase the trehalose levels in the hemolymph when the stick insect is ligated between the head and the thorax. Here, we use two biological assays to assess the potencies of 19 AKH analogs in ligated C. morosus: the carbohydrate-mobilizing assay measures the change in the levels of circulating carbohydrates following injection of a substance, while the semi-exposed heart assay measures a change in heart beat rate after the peptide is applied onto the heart. With the endogenous AKH (Carmo-HrTH-II) as lead peptide, we report here on seven naturally-occurring AKH peptides (bioanalogs) selected for testing because of a single or double amino acid replacement, or for being octapeptides. Single amino acid substitutions by an alanine residue at all positions of Carmo-HrTH-II, as well as analogs modified at the termini were also investigated to give a comprehensive view of ligand-receptor interaction at the physiological level in a hemimetabolous insect that practices thanatosis (feigning death). Only small changes are elicited in the bioassays, but the results from the two tests are comparable bar one or two anomalies. Results show that analogs modified at the termini have no or reduced activity. Regarding structural requirements of a ligand, the C. morosus AKH receptor appears to be strict: octapeptides are not preferred and many of the decapeptide analogs failed to reach 50% activity relative to Carmo-HrTH-II. The data implies that the AKH receptor in C. morosus mostly does not tolerate shorter peptides and single amino acid replacements in most places of the native AKH peptide. This information is important if environmentally friendly insect-specific pesticides are made based on an insect AKH as lead peptide: stick insects that are normally not viewed as pest insects may not be easily targeted by cross-reactive AKH mimetics directed at harmful insects, due to the very specific amino acid requirements to activate the C. morosus AKH receptor.
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Affiliation(s)
- Ottilie K H Katali
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Heather G Marco
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Gerd Gäde
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
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Marco HG, Gäde G. Five Neuropeptide Ligands Meet One Receptor: How Does This Tally? A Structure-Activity Relationship Study Using Adipokinetic Bioassays With the Sphingid Moth, Hippotion eson. Front Endocrinol (Lausanne) 2019; 10:231. [PMID: 31031708 PMCID: PMC6473027 DOI: 10.3389/fendo.2019.00231] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/22/2019] [Indexed: 12/13/2022] Open
Abstract
Adipokinetic hormones (AKHs) play a major role in mobilizing stored energy metabolites during energetic demand in insects. We showed previously (i) the sphingid moth Hippotion eson synthesizes the highest number of AKHs ever recorded, viz. five, in its corpus cardiacum: two octa- (Hipes-AKH-I and II), two nona- (Hipes-AKH-III and Manse-AKH), and one decapeptide (Manse-AKH-II), which are all active in lipid mobilization (1). (ii) Lacol-AKH from a noctuid moth showed maximal AKH activity in H. eson despite sequence differences and analogs based on Lacol-AKH with modifications at positions 2, 3, 8, or at the termini, as well as C-terminally shortened analogs had reduced or no activity (2). Here we report on N-terminally shortened and modified analogs of the lead peptide, as well as single amino acid substitutions at positions 1, 4, 5, 6, and 7 by an alanine residue. Ala1 and Glu1 instead of pGlu are not tolerated well to bind to the H. eson AKH receptor, whereas Gln1 has high activity, suggesting it is endogenously cyclized. Replacing residue 5 or 7 with Ala did not alter activity much, in contrast with changes at position 4 or 6. Similarly, eliminating pGlu1, Leu2, or Thr3 from Lacol-AKH severely interfered with biological activity. This indicates that there is no core peptide sequence that can elicit the adipokinetic effect and that the overall conformation of the active peptide is required for a physiological response. AKHs achieve a biological action through binding to a receptor located on fat body cells. To date, one AKH receptor has been identified in any given insect species; we infer the same for H. eson. We aligned lepidopteran AKH receptor sequences and note that these are very similar. The results of our study is, therefore, also applicable to ligand-receptor interaction of other lepidopteran species. This information is important for the consideration of peptide mimetics to combat lepidopteran pest insects.
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Wahedi A, Gäde G, Paluzzi JP. Insight Into Mosquito GnRH-Related Neuropeptide Receptor Specificity Revealed Through Analysis of Naturally Occurring and Synthetic Analogs of This Neuropeptide Family. Front Endocrinol (Lausanne) 2019; 10:742. [PMID: 31736879 PMCID: PMC6838013 DOI: 10.3389/fendo.2019.00742] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/14/2019] [Indexed: 12/22/2022] Open
Abstract
Adipokinetic hormone (AKH), corazonin (CRZ), and the AKH/CRZ-related peptide (ACP) are neuropeptides considered homologous to the vertebrate gonadotropin-releasing hormone (GnRH). All three Aedes aegypti GnRH-related neuropeptide receptors have been characterized and functionally deorphanized. Individually they exhibit high specificity for their native ligands, prompting us to investigate the contribution of ligand structures in conferring receptor specificity for two of these receptors. Here, we designed a series of analogs based on the native ACP sequence and screened them using a heterologous system to identify critical residues required for ACP receptor (ACPR) activation. Analogs lacking the carboxy-terminal amidation, replacing aromatics, as well as truncated analogs were either completely inactive or had very low activities on ACPR. The polar threonine (position 3) and the blocked amino-terminal pyroglutamate are also critical, whereas ACP analogs with alanine substitutions at position 2 (valine), 5 (serine), 6 (arginine), and 7 (aspartate) were less detrimental including the substitution of charged residues. Replacing asparagine (position 9) with an alanine resulted in a 5-fold more active analog. A naturally-occurring ACP analog, with a conserved substitution in position two, was well tolerated yet displayed significantly reduced activity compared to the native mosquito ACP peptide. Chain length contributes to ligand selectivity in this system, since the endogenous octapeptide Aedae-AKH does not activate the ACPR whereas AKH decapeptides show low albeit significant activity. Similarly, we utilized this in vitro heterologous assay approach against an A. aegypti AKH receptor (AKHR-IA) testing carefully selected naturally-occurring AKH analogs from other insects to determine how substitutions of specific residues in the AKH ligand influence AKHR-IA activation. AKH analogs having single substitutions compared to Aedae-AKH revealed position 7 (either serine or asparagine) was well tolerated or had slightly improved activation whereas changes to position 6 (proline) compromised receptor activation by nearly 10-fold. Substitution of position 3 (threonine) or analogs with combinations of substitutions were quite detrimental with a significant decrease in AKHR-IA activation. Collectively, these results advance our understanding of how two GnRH-related systems in A. aegypti sharing the most recent evolutionary origin sustain independence of function and signaling despite their relatively high degree of ligand and receptor homology.
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Affiliation(s)
- Azizia Wahedi
- Department of Biology, York University, Toronto, ON, Canada
| | - Gerd Gäde
- Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
- *Correspondence: Gerd Gäde
| | - Jean-Paul Paluzzi
- Department of Biology, York University, Toronto, ON, Canada
- Jean-Paul Paluzzi
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Dubos MP, Bernay B, Favrel P. Molecular characterization of an adipokinetic hormone-related neuropeptide (AKH) from a mollusk. Gen Comp Endocrinol 2017; 243:15-21. [PMID: 27823954 DOI: 10.1016/j.ygcen.2016.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/31/2016] [Accepted: 11/03/2016] [Indexed: 12/14/2022]
Abstract
Adipokinetic hormones (AKH) are key regulators of energy mobilization in insects. With the growing number of genome sequence available, the existence of genes encoding AKH related peptides has now been established in protostomes. Here we investigated the occurrence of a mature AKH-like neuropeptide (Cg-AKH) in the oyster Crassostrea gigas. We unambiguously elucidated the primary structure of this neuropeptide by mass spectrometry from peptidic extracts of oyster visceral ganglia. Cg-AKH mature peptide (pQVSFSTNWGS-amide) represents an additional member of the AKH family of peptides. The organization of Cg-AKH encoding gene and its corresponding transcript is also described. Cg-AKH gene was found to be expressed in the nervous system though at extremely low levels compared to other neuropeptide encoding genes such as the oyster GnRH gene. Although both reproduction and feeding are known to affect the energy balance in oysters, no significant differential expression of Cg-AKH gene could be evidenced in relation with the nutritional status or along the reproductive cycle. The possible involvement of Cg-AKH in the regulation of energy balance in oyster remains an open question.
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Affiliation(s)
- Marie-Pierre Dubos
- Normandie Univ, UNICAEN, CNRS 7208, IRD 207, UMR BOREA, Esplanade de la Paix, 14032 Caen cedex, France
| | - Benoit Bernay
- Normandie Univ, UNICAEN, SF 4206 ICORE, Esplanade de la Paix, 14032 Caen cedex, France
| | - Pascal Favrel
- Normandie Univ, UNICAEN, CNRS 7208, IRD 207, UMR BOREA, Esplanade de la Paix, 14032 Caen cedex, France.
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Caers J, Janssen T, Van Rompay L, Broeckx V, Van Den Abbeele J, Gäde G, Schoofs L, Beets I. Characterization and pharmacological analysis of two adipokinetic hormone receptor variants of the tsetse fly, Glossina morsitans morsitans. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 70:73-84. [PMID: 26690928 DOI: 10.1016/j.ibmb.2015.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/05/2015] [Accepted: 11/30/2015] [Indexed: 06/05/2023]
Abstract
Adipokinetic hormones (AKH) are well known regulators of energy metabolism in insects. These neuropeptides are produced in the corpora cardiaca and perform their hormonal function by interacting with specific G protein-coupled receptors (GPCRs) at the cell membranes of target tissues, mainly the fat body. Here, we investigated the sequences, spatial and temporal distributions, and pharmacology of AKH neuropeptides and receptors in the tsetse fly, Glossina morsitans morsitans. The open reading frames of two splice variants of the Glomo-akh receptor (Glomo-akhr) gene and of the AKH neuropeptide encoding genes, gmmhrth and gmmakh, were cloned. Both tsetse AKHR isoforms show strong sequence conservation when compared to other insect AKHRs. Glomo-AKH prepropeptides also have the typical architecture of AKH precursors. In an in vitro Ca(2+) mobilization assay, Glomo-AKH neuropeptides activated each receptor isoform up to nanomolar concentrations. We identified structural features of tsetse AKH neuropeptides essential for receptor activation in vitro. Gene expression profiles suggest a function for AKH signaling in regulating Glossina energy metabolism, where AKH peptides are released from the corpora cardiaca and activate receptors mainly expressed in the fat body. This analysis of the ligand-receptor coupling, expression, and pharmacology of the two Glomo-AKHR variants facilitates further elucidation of the function of AKH in G. m. morsitans.
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Affiliation(s)
- Jelle Caers
- Functional Genomics and Proteomics, Department of Biology, KU Leuven, Naamsestraat 59, 3000, Leuven, Belgium.
| | - Tom Janssen
- Functional Genomics and Proteomics, Department of Biology, KU Leuven, Naamsestraat 59, 3000, Leuven, Belgium.
| | - Liesbeth Van Rompay
- Functional Genomics and Proteomics, Department of Biology, KU Leuven, Naamsestraat 59, 3000, Leuven, Belgium.
| | - Valérie Broeckx
- Functional Genomics and Proteomics, Department of Biology, KU Leuven, Naamsestraat 59, 3000, Leuven, Belgium.
| | - Jan Van Den Abbeele
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerpen, Belgium; Laboratory of Zoophysiology, Department of Physiology, University of Ghent, Krijgslaan 281, 9000, Ghent, Belgium.
| | - Gerd Gäde
- Department of Biological Sciences, University of Cape Town, Private Bag, 7701, Rondebosch, South Africa.
| | - Liliane Schoofs
- Functional Genomics and Proteomics, Department of Biology, KU Leuven, Naamsestraat 59, 3000, Leuven, Belgium.
| | - Isabel Beets
- Functional Genomics and Proteomics, Department of Biology, KU Leuven, Naamsestraat 59, 3000, Leuven, Belgium.
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Marco HG, Gäde G. Structure-activity relationship of adipokinetic hormone analogs in the striped hawk moth, Hippotion eson. Peptides 2015; 68:205-10. [PMID: 25656401 DOI: 10.1016/j.peptides.2015.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/26/2015] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
Abstract
We showed previously that the sphingid moth Hippotion eson synthesizes the highest number of adipokinetic hormones (AKHs) ever recorded, viz. five, in its corpus cardiacum: two octa-, two nona- and one decapeptide. Further, the endogenous decapeptide (Manse-AKH-II) and the other four AKHs are all active in lipid mobilization, whereas a non-lepidopteran decapeptide (Lacsp-AKH, five amino acid substitutions compared with Manse-AKH-II), was inactive in H. eson. We tested the decapeptide, Lacol-AKH, from a noctuid moth for the first time in a bioassay and it shows a maximal AKH effect in H. eson. Lacol-AKH differs from Manse-AKH-II in three places and from Lacsp-AKH in four places. We, thus, used Lacol-AKH as a lead peptide on which a series of AKH analogs are based to represent: (a) single amino acid replacements (according to the substitutions in Lacsp-AKH), (b) shorter chain lengths, (c) modified termini, and (d) a replacement of Trp in position 8. These analogs, as well as a few naturally occurring AKHs from other lepidopterans were tested in in vivo adipokinetic assays to gain insight into the ligand-receptor interaction in H. eson. Our results show that the second and third amino acids are important for biological activity in the sphingid moth. Analogs with an N-[acetylated]Glu(1) (instead of a pyroGlu), or a free C-terminus, or Ala(8) were not active in the bioassays, while shortened Lacol-AKH analogs and the undecapeptide, non-amidated Vanca-AKH showed very reduced activity (below 25%). This information is important for the consideration of peptide mimetics to combat specific lepidopteran pest insects.
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Affiliation(s)
- Heather G Marco
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa.
| | - Gerd Gäde
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
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Caers J, Peeters L, Janssen T, De Haes W, Gäde G, Schoofs L. Structure-activity studies of Drosophila adipokinetic hormone (AKH) by a cellular expression system of dipteran AKH receptors. Gen Comp Endocrinol 2012; 177:332-7. [PMID: 22569168 DOI: 10.1016/j.ygcen.2012.04.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 04/18/2012] [Accepted: 04/23/2012] [Indexed: 11/19/2022]
Abstract
Structure-activity studies for the adipokinetic hormone receptor of insects were for the first time performed in a cellular expression system. A series of single amino acid replacement analogues for the endogenous adipokinetic hormone of Drosophila melanogaster (pGlu-Leu-Thr-Phe-Ser-Pro-Asp-Trp-NH(2)) were screened for activity with a bioluminescence cellular assay, expressing the G-protein coupled receptor. For this series of peptide analogues, one amino acid of the N-terminal tetrapeptide was successively replaced by alanine, while those of the C-terminal tetrapeptide were successively substituted by glycine; other modifications included the blocked N- and C-termini that were replaced by an acetylated alanine and a hydroxyl group, respectively. The analogue series was tested on the AKH receptors of two dipteran species, D. melanogaster and Anopheles gambiae. The blocked termini of the AKH peptide probably play a minor role in receptor interaction and activation, but are considered functionally important elements to protect the peptide against exopeptidases. In contrast, the amino acids at positions 2, 3, 4 and 5 from the N-terminus all seem to be crucial for receptor activation. This can be explained by the potential presence of a β-strand in this part of the peptide that interacts with the receptor. The inferred β-strand is probably followed by a β-turn in which the amino acids at positions 5-8 are involved. In this β-turn, the residues at positions 6 and 8 seem to be essential, as their substitutions induce only a very low degree of receptor activation. Replacement of Asp(7), by contrast, does not influence receptor activation at all. This implies that its side chain is folded inside the β-turn so that no interaction with the receptor occurs.
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Affiliation(s)
- Jelle Caers
- Research Group of Functional Genomics and Proteomics, KU Leuven, Naamsestraat 59, B-3000 Leuven, Belgium.
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QSAR Study on Insect Neuropeptide Potencies Based on a Novel Set of Parameters of Amino Acids by Using OSC-PLS Method. Int J Pept Res Ther 2011. [DOI: 10.1007/s10989-011-9258-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Potencies of naturally-occurring AKH/RPCH peptides in Locusta migratoria in the acetate uptake assay in vitro and comparison with their potencies in the lipid mobilisation assay in vivo. ACTA BIOLOGICA HUNGARICA 2000. [DOI: 10.1007/bf03543236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Lee MJ, de Jong S, Gäde G, Poulos C, Goldsworthy GJ. Mathematical modelling of insect neuropeptide potencies. Are quantitatively predictive models possible? INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2000; 30:899-907. [PMID: 10899456 DOI: 10.1016/s0965-1748(00)00078-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The potencies of natural adipokinetic hormones and synthetic variants have been determined in Locusta migratoria using the lipid mobilisation assay in vivo, and/or the acetate uptake assay in vitro. These data are combinations of previously published and unpublished data (a total of sixty-nine analogues), and form data sets for the construction of mathematical models of the hormone potencies. The sequence variations of amino acids in both natural and artificial adipokinetic hormone analogues were described using continuous descriptor scales z(1)', z(2)', and z(3)', each previously published scale being derived from various properties of the amino acids. By means of these z'-scales and partial least squares regression we attempted to model the potencies in Locusta migratoria of adipokinetic hormones in the two assays. Correlations (r(2) values) between predicted and actual potencies of the different peptides were up to 0.73. We discuss the potential of the partial least squares method for formulating quantitative relationships between different hormone structures and their potencies, and describe how the procedure might be used in structure-activity prediction with the construction of an optimised peptide data set.
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Affiliation(s)
- M J Lee
- Biotechnology, Unilever Research Vlaardingen, Olivier van Noortlaan 120, 3133 AT, Vlaardingen, The Netherlands.
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Velentza A, Spiliou S, Poulos CP, Goldsworthy GJ. Synthesis and biological activity of adipokinetic hormone analogues with modifications in the 4-8 region. Peptides 2000; 21:631-7. [PMID: 10876045 DOI: 10.1016/s0196-9781(00)00200-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Several structural characteristics in the molecule of the locust adipokinetic hormone, AKH-I, have been investigated in terms of their importance in determining biologic activity. All modifications tested in this study resulted in analogues with decreased potency in comparison with the parent molecule. However, all analogues that were found to be active gave a full response, although often only at very high doses of peptide. This study has highlighted for the locust receptor(s) the vital role of the side chain of Thr(5), and the importance of positions 4 and 8. For example, when Trp(8) and Phe(4) were exchanged, the resulting analogue (Trp(4),Phe(8)-AKH-I) was one of the least active analogues tested in this study. Although Trp is tolerated quite well as a substitute for Phe(4), with only a 10-fold loss of potency, Phe is not favored as a substitute for Trp(8) (>300 times decrease in potency). On the other hand, 3-[2-napthyl] alanine (Nal) is a better substitute for Trp(8) (only a 100-fold loss in potency). We conclude that position 4 requires a phenyl ring in the side chain, and position 8 an indole ring.
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Affiliation(s)
- A Velentza
- Department of Chemistry, University of Patras, 26500, Patras, Greece
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Goldsworthy GJ, Lee MJ, Luswata R, Drake AF, Hyde D. Structures, assays and receptors for locust adipokinetic hormones. Comp Biochem Physiol B Biochem Mol Biol 1997; 117:483-96. [PMID: 9297796 DOI: 10.1016/s0305-0491(97)00186-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This review is concerned mainly with the adipokinetic hormones (AKHs) of locusts: their molecular conformations, actions and functions and the development of microfiltration assays in vitro. The physiological significance of having multiple hormones with overlapping actions whose efficacy changes during development is discussed in relation to the possibility that these reflect variations in populations of receptors and/or the pharmacokinetics of the peptides. The involvement of second messengers in the transduction mechanism of AKHs is reviewed, and we describe hormone-induced changes of intracellular calcium in single dispersed fat body cells. The structure activity relationships of the three locust AKHs and a number of analogues with variations at the N- and C-termini are discussed. A number of areas are identified where there are gaps in our understanding of these hormones, and some of these will be the focus of our future research.
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Affiliation(s)
- G J Goldsworthy
- Department of Biology, Birkbeck College, University of London, U.K
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