Pyrokinin/PBAN radio-receptor assay: development and application for the characterization of a putative receptor from the pheromone gland of Heliothis peltigera

A radio-receptor assay (RRA) for the insect pyrokinin/PBAN family has been developed. The development involved examination of the ligand (3H-tyrosyl-PBAN28-33NH2)-receptor interaction under various incubation conditions and variations on sex pheromone gland membrane preparation. Application of the RRA for a partial characterization of the putative pyrokinin/PBAN receptor in the pheromone gland of H. peltigera revealed age-dependence of its expression. Pharmacological characterization revealed a high correlation between the binding-affinity to the receptor of various PBAN-derived peptides and their in vivo pheromonotropic bioactivity, and shed light on the interaction of backbone cyclic and linear ([Arg27,D-Phe30]PBAN28-33NH2) PBAN antagonists with the receptor.     

Cloning and characterization of the pheromone biosynthesis activating neuropeptide receptor gene in Spodoptera littoralis larvae

In noctuid moths cuticular pigmentation is regulated by the pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family, which also mediates a variety of other functions in moths and other insects. Numerous studies have shown that these neuropeptides exert their functions through activation of the PBAN receptor (PBAN-R), with subsequent Ca(2+) influx, followed by either activation of cAMP or direct activation of downstream kinases. Recently, several PBAN-Rs have been identified, all of which are from the pheromone gland of adult female moths, but evidence shows that functional PK/PBAN-Rs can also be expressed in insect larvae, where they mediate melanization and possibly other functions (e.g., diapause). Here, we identified a gene encoding a G-protein-coupled receptor from the 5th instar larval tissue of the moth Spodoptera littoralis. The cDNA of this gene contains an open reading frame with a length of 1050 nucleotides, which translates to a 350-amino acid, 42-kDa protein that shares 92% amino acid identity with Helicoverpa zea and Helicoverpa armigera PBAN-R, 81% with Bombyx mori PBAN-R and 72% with Plutella xylostella PBAN-R. The S. littoralis PBAN-R gene was stably expressed in NIH3T3 cells and transiently in HEK293 cells. We show that it mediates the dose-dependent PBAN-induced intracellular Ca(2+) response and activation of the MAP kinase via a PKC-dependent but Galphai-independent signaling mechanism. Other PK/PBAN family peptides (pheromonotropin and a C-terminally PBAN-derived peptide PBAN(28-33)NH(2)) also triggered MAP kinase activation. This receptor, together with the previously cloned PBAN-R, may facilitate our understanding of the cell-specific responses and functional diversities of this diverse neuropeptide family.     

Characterization of a putative pheromone biosynthesis-activating neuropeptide (PBAN) receptor from the pheromone gland of Heliothis peltigera

The binding of [(3)H]tyrosyl-PBAN28-33NH(2) to pheromone gland membranes of the moth Heliothis peltigera was investigated. The study describes the development of a pheromone biosynthesis-activating neuropeptide (PBAN) radioreceptor assay and demonstrates the presence of a putative PBAN binding site on the pheromone gland. It also describes synthesis of a radioligand and optimization of binding conditions with respect to membrane preparation, number of gland equivalents, kinetics of ligand binding and composition of the binding solution. Binding was found to be optimal when membranes were freshly prepared from frozen glands, incubated at a concentration of one gland equivalent per reaction tube in the presence of 10 mM HCO(3)(-) ions. Equilibrium of ligand binding was obtained after 20 min. Presence of other components such as NaCl, KCl or SH reagents did not have any effect on binding. Binding was found to be saturable, with a K(d) of 5.73 +/- 1.05 x 10(-6) M and a Bmax of 1.85 +/- 0.22 nmol/mg protein. Binding was effectively displaced by unlabeled PBAN1-33NH(2) and PBAN28-33NuEta(2) with a K(i) of 4.3 +/- 1.1 x 10(-6) M and 4.9 +/- 2.6 x 10(-6) M, respectively.     

PBAN selective antagonists: inhibition of PBAN induced cuticular melanization and sex pheromone biosynthesis in moths

A D-Phe scan (sequential D-Phe replacement) library of linear peptides, synthesized on the basis of a slightly modified active sequence of PBAN (YFSPRL-amide) was employed to detect potential inhibitors of cuticular melanization in Spodoptera littoralis larvae and to compare their stimulatory and inhibitory melanization activity with their pheromonotropic agonistic and antagonistic activities. A quantitative melanotropic assay was used to monitor the extent of cuticular melanization elicited by Hez-PBAN1-33NH2 in S. littoralis larvae in the presence and absence of the D-Phe peptides. The data revealed the presence of two partial melanotropic antagonists, and disclosed the presence of selective pure melanotropic agonists and pure pheromonotropic antagonists indicating differences in the inhibitory and stimulatory patterns of the library with respect to both activities. The differences between the pheromonotropic and melanotropic inhibitory patterns of the peptides hints at the possibility that sex pheromone biosynthesis in the pheromone gland of Heliothis peltigera females and induction of cuticular melanization in S. littoralis may be mediated by different receptors (that may result either from presence of different receptor sub-types or may reflect species differences in receptor structure and/or properties) despite the fact that they are induced by the same peptide (PBAN1-33NH2).     

Role of neuropeptides in sex pheromone production in moths

Sex pheromone biosynthesis in many moth species is controlled by a cerebral neuropeptide, termed pheromone biosynthesis activating neuropeptide (PBAN). PBAN is a 33 amino acid C-terminally amidated neuropeptide that is produced by neuroendocrine cells of the subesophageal ganglion (SEG). Studies of the regulation of sex pheromone biosynthesis in moths have revealed that this function can be elicited by additional neuropeptides all of which share the common C-terminal pentapeptide FXPRL-amide (X = S, T, G, V). In the past two decades extensive studies were carried out on the chemical, cellular and molecular aspects of PBAN and the other peptides (termed the pyrokinin (PK)/PBAN family) aiming to understand the mode of their action on sex pheromone biosynthesis. In the present review we focus on a few of these aspects, specifically on the: (i) structure-activity relationship (SAR) of the PK/PBAN family, (ii) characterization of the PK/PBAN receptor and (iii) development of a novel strategy for the generation of PK/PBAN antagonists and their employment in studying the mode of action of the PK/PBAN peptides.     

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

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.     

Potent activity of a PK/PBAN analog with an (E)-alkene,trans-Pro mimic identifies the Pro orientation and core conformation during interaction with HevPBANR-C receptor

The pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family plays a multifunctional role in an array of important physiological processes in insects, including regulation of sex pheromone biosynthesis in moths. A cyclic PK/PBAN analog (cyclo[NTSFTPRL]) retains significant activity on the pheromonotropic HevPBANR receptor from the tobacco budworm Heliothis virescens expressed in CHO-K1 cells. Previous studies indicate that this rigid, cyclic analog adopts a type I β-turn with a transPro over residues TPRL within the core PK/PBAN region. An analog containing an (E)-alkene, trans-Pro mimetic motif was synthesized, and upon evaluation on the HevPBANR receptor found to have an EC₅₀ value that is not statistically different from a parent C-terminal PK/PBAN hexapeptide sequence. The results, in aggregate, provide strong evidence for the orientation of Pro and the core conformation of PK/PBAN neuropeptides during interaction with the expressed PBAN receptor. The work further identifies a novel scaffold with which to design mimetic PBAN analogs as potential leads in the development of environmentally favorable pest management agents capable of disrupting PK/PBAN-regulated pheromone signaling systems.     

Identification of Functionally Important Residues of the Silkmoth Pheromone Biosynthesis-activating Neuropeptide Receptor,an Insect Ortholog of the Vertebrate Neuromedin U Receptor

The biosynthesis of sex pheromone components in many lepidopteran insects is regulated by the interaction between pheromone biosynthesis-activating neuropeptide (PBAN) and the PBAN receptor (PBANR), a class A G-protein-coupled receptor. To identify functionally important amino acid residues in the silkmoth PBANR, a series of 27 alanine substitutions was generated using a PBANR chimera C-terminally fused with enhanced GFP. The PBANR mutants were expressed in Sf9 insect cells, and their ability to bind and be activated by a core PBAN fragment (C10PBAN^R2K) was monitored. Among the 27 mutants, 23 localized to the cell surface of transfected Sf9 cells, whereas the other four remained intracellular. Reduced binding relative to wild type was observed with 17 mutants, and decreased Ca²⁺ mobilization responses were observed with 12 mutants. Ala substitution of Glu-95, Glu-120, Asn-124, Val-195, Phe-276, Trp-280, Phe-283, Arg-287, Tyr-307, Thr-311, and Phe-319 affected both binding and Ca²⁺ mobilization. The most pronounced effects were observed with the E120A mutation. A molecular model of PBANR indicated that the functionally important PBANR residues map to the 2nd, 3rd, 6th, and 7th transmembrane helices, implying that the same general region of class A G-protein-coupled receptors recognizes both peptidic and nonpeptidic ligands. Docking simulations suggest similar ligand-receptor recognition interactions for PBAN-PBANR and the orthologous vertebrate pair, neuromedin U (NMU) and NMU receptor (NMUR). The simulations highlight the importance of two glutamate residues, Glu-95 and Glu-120, in silkmoth PBANR and Glu-117 and Glu-142 in human NMUR1, in the recognition of the most functionally critical region of the ligands, the C-terminal residue and amide.     

Pheromonotropic stimulation of moth pheromone gland cultures in vitro

The direct neurohormonal control of pheromone biosynthesis by pheromone biosynthesis activating neuropeptide (PBAN) was demonstrated in Helicoverpa (Heliothis) spp. using pheromone gland cultures in vitro. Pheromone gland activation involved the de novo production of the main pheromone component (Z)-11-hexadecenal as revealed by radio-TLC, radio-HPLC, and radio-GC. Activation was found to be a specific response attributed to pheromone gland cultures alone. Specificity of pheromonotropic activation was demonstrated to be limited to nervous tissue extracts. A sensitive and specific radioimmunoassay was developed using [³H]-PBAN, and the spatial and temporal distribution of PBAN-immunore-activity was studied. PBAN-immunoreactivity in brain complexes was found throughout the photoperiod and in all ages. From the distribution of PBAN-immunoreactivity it appears that PBAN release is affected by photoperiod. Pheromone gland cultures were found to be competent to pheromone production irrespective of age and photoperiod. Therefore, the neuroendocrine control of pheromone production operates at the level of neuropeptide synthesis and/or release and not at the level of the target tissue itself. The involvement of cyclic-AMP as a second messenger system was demonstrated. Brain extracts and PBAN were shown to stimulate dose- and time-dependent changes in intracellular cyclic-AMP levels. The role of cyclic-AMP in this mechanism was further verified by the ability of cyclic-AMP mimetics to mimic the pheromonotropic effect of brain extracts and PBAN. However, dose-response studies using PBAN and a hexapeptide C-terminal fragment of PBAN suggested that PBAN induces a two mechanism response, one occurring at low PBAN concentrations (high affinity receptor) and another at higher PBAN concentrations (low affinity receptor). Further evidence indicating a dual receptor system was obtained with the observation that the active phorbol ester (phorbol-12-myristate 13-acetate), the diacyl-glycerol analog (1,2-dioleolyl-sn-glycerol), and the intracellular calcium ionophore (ionomycin) mimicked the physiological action of PBAN and that lithium chloride had a pheromonostatic effect. The results indicate that pheromone glands also possess receptors that are linked to inositol phosphate hydolysis. © 1994 Wiley-Liss, Inc.     

昆虫神经肽PBAN的细胞内信号转导

昆虫性信息素多数为长链的不饱和醇、醋酸酯、醛或酮类,链长一般为10-20碳,主要在性信息素腺体内由乙酰辅酶A经过脂肪酸合成、碳链缩短、去饱和以及碳酰基的还原修饰等步骤合成的;而性信息素合成激活肽(pheromone biosynthesis activating neuropeptide,PBAN)是由昆虫食管下神经节中的部分神经细胞合成和分泌的神经肽,通常由33个氨基酸组成,在C-末端有一个相同的五肽序列,主要调控性信息素的生物合成。有关PBAN的细胞内信号转导是近几年的研究热点,研究显示 PBAN首先与性信息素腺体细胞表面的G蛋白偶联受体结合,随后依据昆虫种类的不同,其细胞内信号转导方式主要有三种:(1)以cAMP信号传导途径进行信号转导;(2)以cAMP和磷脂酰肌醇信号传导途径共同进行信号转导;(3)主要以Ca2 为第二信使进行信号传导。     

Discovery of a linear lead antagonist to the insect pheromone biosynthesis activating neuropeptide (PBAN)

We report the discovery of a linear lead antagonist for the insect pheromone biosynthesis activating neuropeptide (PBAN) which inhibits sex pheromone biosynthesis in the female moth Heliothis peltigera. Two approaches have been used in attempting to convert PBAN agonists into antagonists. The first involved omission of the C-terminal amide and reduction of the sequence from the N-terminus in a linear library based on PBAN 1-33NH(2.) The second involved replacement of L amino-acids by the D hydrophobic amino acid D-Phe in a linear library based on PBAN28-33NH(2.) Screening of the two libraries for pheromonotropic antagonists resulted in the disclosure of one compound out of the D-Phe library (Arg-Tyr-Phe-D-Phe-Pro-Arg-Leu-NH(2)) which inhibited sex pheromone production by 79 and 64% at 100 pmol in two moth colonies and exhibited low agonistic activity. Omission of the C-terminal amide in PBAN 1-33NH(2) and its shorter analogs did not lead to the discovery of an antagonistic compound.     

Physiological Mechanisms of Pheromonostatic Responses: effects of Adrenergic Agonists and Antagonists on Moth (Helicoverpa armigera) Pheromone Biosynthesis

The adrenergic agonists octopamine, tyramine and clonidine inhibited the normal pheromonotropic action due to PBAN (pheromone biosynthesis activating neuropeptide) in incubations of intersegmental tissues that are situated between the 8th and 9th abdominal segments of the moth ovipositor tip. This inhibition was reversed in the presence of the adrenergic antagonists phentolamine, yohimbine and chlorpromazine. Incubations of 8th segments alone, which do not produce pheromone, resulted in elevated levels of intracellular cAMP in the presence of octopamine. The physiological significance of this phenomenon is unclear. However, clonidine (an alpha(2) selective agonist) did not duplicate octopamine stimulation of intracellular cAMP in 8th segment cultures. In intersegmental membrane cultures clonidine successfully duplicated the octopamine inhibition of both pheromone and intracellular cAMP production. The physiological significance of octopaminergic receptors mediating the inhibitory response of intersegments was investigated by experiments in vivo. When PBAN was injected into photophase females the normal pheromonotropic activity due to the injected PBAN dropped after 2h. In the presence of clonidine, normal peak stimulatory levels were never attained and a faster decline was observed. Clonidine also inhibited the pheromonotropic response of 24h-decapitated females to PBAN. Adrenergic antagonists successfully reversed the inhibitory effect of clonidine in decapitated females, but did not reverse the effect of clonidine in photophase females. In addition, when clonidine was injected into female moths during the scotophase normal peak pheromone titers were reduced although no effect on calling behavior was observed. Copyright 1997 Elsevier Science Ltd. All rights reserved     

Mechanisms involved in the control of pheromone production in female moths: recent developments

Species‐specific pheromone blends of nocturnal female moths, derived from fatty acid precursors, are produced and released for mate‐finding, and are initiated by the circadian, trophic hormone, Pheromone Biosynthesis Activating Neuropeptide (PBAN). PBAN, produced in the sub‐oesophageal ganglion, is a 33 amino acid neuropeptide with a minimum active core in its FXPRLamide C‐terminal. PBAN acts directly on pheromone gland cells of mature females by binding to a specific G‐protein‐coupled membrane receptor (GPCR), and thereby initiating a signal transduction cascade involving calcium and cAMP. This discussion will review recent developments concerning the identification of the PBAN GPCR, its regulation by juvenile hormone (JH), and its mode of action at the level of the pheromone biosynthetic pathway. The discussion will also include recent developments concerning events occurring as a result of the transfer of pheromonostatic compounds of male origin after mating.     

RNA interference of PBAN receptor suppresses expression of two fatty acid desaturases in female Plutella xylostella

Pheromone biosynthesis-activating neuropeptide (PBAN) stimulates sex pheromone biosynthesis by activating PBAN receptor (PBANr), which triggers a specific signal transduction in the pheromone gland cells. We have shown that RNA interference (RNAi) of PBANr of Plutella xylostella significantly suppressed pheromone biosynthesis and subsequent mating behavior. In order to assess molecular events occurring downstream of PBAN signaling, we cloned partial sequences of Δ9 and Δ11 fatty acid desaturases of P. xylostella. Phylogenetic analysis indicated that these two desaturase genes were highly clustered with other desaturases associated with sex pheromone biosynthesis in other insects. RT-PCR analysis showed that Δ9 desaturase was dominantly expressed in adult females, whereas Δ11 desaturase was expressed in all P. xylostella developmental stages. When PBANr expression was suppressed by PBANr-RNAi, the treated females also showed significant suppression of expression of both desaturases. These results suggest that expressions of the two desaturases are controlled by PBAN and that the two desaturases may be involved as downstream components in sex pheromone biosynthesis of P. xylostella.     

An amphiphilic, PK/PBAN analog is a selective pheromonotropic antagonist that penetrates the cuticle of a heliothine insect

A linear pyrokinin (PK)/pheromone biosynthesis activating neuropeptide (PBAN) antagonist lead (RYF[dF]PRLa) was structurally modified to impart amphiphilic properties to enhance its ability to transmigrate the hydrophobic cuticle of noctuid moth species and yet retain aqueous solubility in the hemolymph to reach target PK/PBAN receptors within the internal insect environment. The resulting novel PK/PBAN analog, Hex-Suc-A[dF]PRLa (PPK-AA), was synthesized and evaluated as an antagonist in a pheromonotropic assay in Heliothis peltigera against 4 natural PK/PBAN peptide elicitors (PBAN; pheromonotropin, PT; myotropin, MT; leucopyrokinin, LPK) and in a melanotropic assay in Spodoptera littoralis against 3 natural PK/PBAN peptide elicitors (PBAN, PT, LPK). The analog proved to be a potent and efficacious inhibitor of sex pheromone biosynthesis elicited by PBAN (84% at 100 pmol) and PT (54% at 100 pmol), but not by MT and LPK. PPK-AA is a selective pure antagonist (i.e., does not exhibit any agonistic activity) as it failed to inhibit melanization elicited by any of the natural PK/PBAN peptides. The analog was shown to transmigrate isolated cuticle dissected from adult female Heliothis virescens moths to a high extent of 25-30% (130-150 pmol), representing physiologically significant quantities. PPK-AA represents a significant addition to the arsenal of tools available to arthropod endocrinologists studying the endogenous mechanisms of PK/PBAN regulated processes, and a prototype for the development of environmentally friendly pest management agents capable of disrupting the critical process of reproduction.     

Evidence for both humoral and neural regulation of sex pheromone biosynthesis in Spodoptera littoralis

Selected tissues presumably involved in the control of sex pheromone production were analyzed by ELISA for the presence of PBAN-like immunoreactivity (PBAN-IR) in Spodoptera littoralis. The temporal distribution pattern of PBAN-IR in the hemolymph is similar to that of pheromone production in the gland. On the other hand, analysis of the retrocerebral complex, brain-subesophageal ganglion complex, and terminal abdominal ganglion (TAG) revealed similar PBAN-IR levels in both photophase and scotophase periods. Pheromonotropic activity exhibited by both hemolymph and TAG, as determined by a modified in vitro bioassay, agrees with the results of the immunochemical analyses. Severing the ventral nerve cord anterior to the TAG impaired normal sex pheromone production by second-scotophase females. These results are discussed in the context of how sex pheromone biosynthesis is regulated by PBAN in S. littoralis. © 1996 Wiley-Liss, Inc.     

Effect of synthetic pban and derived peptides on sex pheromone biosynthesis in Heliothis peltigera (Lepidoptera: Noctuidae)

The activity of synthetic Heliothis zea PBAN (Hez-PBAN) and four shorter peptides on the sex pheromone biosynthesis in Heliothis peltigera was investigated in order to characterize their biological potency, and to determine the structure-activity relationship. Hez-PBAN (PBAN 1–33) is very potent and stimulates sex pheromone biosynthesis at the picomolar range both in photophase and scotophase. Removal of eight amino acids from the N-terminal region of the peptide Hez-PBAN had only a minor effect on the biological activity. A shorter fragment of Hez-PBAN, lacking 18 amino acids from the N-terminus, was less active. Two short peptides, consisting of eight and six amino acids, derived from the C-terminal region of Hez-PBAN had very little biological activity. In addition, it was found that PBAN 1–33 undergoes oxidation during storage. The oxidation of the peptide resulted in a loss of its biological activity, which could be restored by reduction with N-methylmercaptoacetamide. Unlike PBAN 1–33, PBAN 9–33 did not lose activity as a function of time, and its activity was fully preserved after prolonged storage. The results indicate that PBAN 1–33 and PBAN 9–33 have similar activities, and that the sequence containing the eight N-terminal amino acids is not essential for the biological activity of Hez-PBAN on the biosynthesis of H. peltigera sex pheromone.     

Binding and signaling of angiotensin-(1-7) in bovine kidney epithelial cells involves the AT(4) receptor

Angiotensin-(1-7) decreased mitogen-activated protein (MAP) kinase (Erks) activation in cultured Mardin-Darby bovine kidney (MDBK) epithelial cells. Also, saturable, high-affinity (125)I-angiotensin-(1-7) binding was detected in MDBK cell membranes. Together, the data suggested the possible presence of an angiotensin-(1-7) receptor. However, ligand structure-binding studies revealed that angiotensin-(3-7) and AT(4) receptor ligands competed with high-affinity for (125)I-angiotensin-(1-7) binding. Furthermore, angiotensin-(3-7) and AT(4) receptor ligands decreased MAP kinase activation in MDBK cells. These results demonstrate that NH(2)-terminal-deleted metabolites of angiotensin-(1-7) can bind with high affinity to the AT(4) receptor and regulate the MAP kinase/Erk signaling pathway in renal epithelial cells.     

RNA interference of pheromone biosynthesis-activating neuropeptide receptor suppresses mating behavior by inhibiting sex pheromone production in Plutella xylostella (L.)

Sex pheromone production is regulated by pheromone biosynthesis-activating neuropeptide (PBAN) in many lepidopteran species. We cloned a PBAN receptor (Plx-PBANr) gene from the female pheromone gland of the diamondback moth, Plutella xylostella (L.). Plx-PBANr encodes 338 amino acids and has conserved structural motifs implicating in promoting G protein coupling and tyrosine-based sorting signaling along with seven transmembrane domains, indicating a typical G protein-coupled receptor. The expression of Plx-PBANr was found only in the pheromone gland of female adults among examined tissues and developmental stages. Heterologous expression in human uterus cervical cancer cells revealed that Plx-PBANr induced significant calcium elevation when challenged with Plx-PBAN. Female P. xylostella injected with double-stranded RNA specific to Plx-PBANr showed suppression of the receptor gene expression and exhibited significant reduction in pheromone biosynthesis, which resulted in loss of male attractiveness. Taken together, the identified PBAN receptor is functional in PBAN signaling via calcium secondary messenger, which leads to activation of pheromone biosynthesis and male attraction.