Silk Moth Neuropeptide Hormones: Prothoracicotropic Hormone and Others

Silk worm (Bombyx Mori) protein, have been considered as potential materials for a variety of advanced engineering and biomedical applications for decades. Recently, silkworm silk has gained significant importance in research attention mainly because of its remarkable and exceptional mechanical properties. Silk has already been shown to have unique interactions with cells in tissues through bio-recognition units. The natural silk contains fibroin and sericin and has been used in various tissues of the human body (skin, bone, nerve, and so on). Besides, silk also still has anti-cancer, anti-tyrosinase, anti-coagulant, anti-oxidant, anti-bacterial, and antidiabetic properties. This article is supposed to describe the diverse biomedical capabilities of B. Mori silk as the appropriate biomaterial among the assorted natural and artificial polymers that are presently accessible, and ideal for usage in regenerative medicine fields.

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“…These materials have a softer touch and gentler sheen (Fu et al, 2015;Nagata et al, 2005;Saric & Scheibel, 2019).…”

Section: Structure and Types Of Silkmentioning

confidence: 99%

Biomedical applications of silkworm ( Bombyx Mori ) proteins in regenerative medicine (a narrative review)

Khosropanah

Vaghasloo

Shakibaei

et al. 2021

J Tissue Eng Regen Med

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“…The ligand PTTH exhibits quite high target specificity between insect species. The hormones from Bombyx mori and Manduca sexta induced adult development of the same insect species, but not of the different one 25 26 . Torso must recognize the differences in the PTTH structures between the insect species.…”

Section: Discussionmentioning

confidence: 91%

Ligand-dependent responses of the silkworm prothoracicotropic hormone receptor, Torso, are maintained by unusual intermolecular disulfide bridges in the transmembrane region

Konogami

Yang

Ogihara

et al. 2016

Sci Rep

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The insect membrane-protein, Torso, is a member of the receptor-tyrosine-kinase family, and is activated by its ligand, prothoracicotropic hormone (PTTH). Although PTTH is one of the most important regulators of insect development, the mechanism of Torso activation by the hormone has remained elusive. In this study, using heterologous expression in cultured Drosophila S2 cells, we detected ligand-independent dimerization of silkworm Torso, and found that the receptor molecules in the dimer were linked by intermolecular disulfide bridges. By examining the oligomerization states of several truncation and substitution mutants of Torso, atypical cysteine residues in the transmembrane region were identified as being responsible for the intermolecular linkage in the dimer. The replacement of all of the cysteines in the region with phenylalanines abolished the disulfide-bond-mediated dimerization; however, non-covalent dimerization of the mutant was detected using a cross-linking reagent, both with and without ligand stimulation. This non-covalent dimerization caused apparent receptor autophosphorylation independently of the ligand stimulation, but did not promote the ERK phosphorylation in the downstream signaling pathway. The unique Torso structure with the intermolecular disulfide bridges in the transmembrane region is necessary to maintain the liganddependent receptor functions of autophosphorylation and downstream activation.Cellular-membrane receptors play important roles as mediators, in the signal transduction of extracellular stimuli to the activation of intracellular biochemical pathways. The receptors are composed of several types of membrane proteins, such as G-protein-coupled receptors (GPCRs), enzyme-linked receptors, ion-channel-linked receptors, and others 1 . To perform their transduction activities, GPCRs usually require other protein partners such as G-proteins, while the enzyme-linked receptors can activate the intracellular pathways by themselves, using the catalytic domains in their own intracellular regions. For example, receptor tyrosine kinases (RTKs) commonly have intracellular tyrosine kinase domains, which phosphorylate the tyrosine residues of the receptors themselves and those within other intracellular protein molecules.Insects also utilize cellular-membrane RTKs to receive extracellular hormonal signals. Among the insect hormonal receptors, Torso, a member of the RTK family, was recently reported to contribute to the activation of prothoracic gland cells in response to stimulation by prothoracicotropic hormone (PTTH) 2 , although Torso was originally discovered as an anteroposterior axis determinant in Drosophila embryos [3][4][5] . In Drosophila larvae, Torso is expressed specifically in the prothoracic glands, and the torso knock-down caused delayed larval development 2 . This phenotype of the knocked-down larvae may be derived from the lack of the molting hormone,

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“…The neurosecretory hormone bombyxin is an insulin-like peptide found in the order Lepidoptera (butter ies and moths). Bombyxin was rst identi ed in the silkworm, Bombyx mori ( In all insects, PTTH acts on the prothoracic glands (PGs), which initiate ecdysone synthesis (Nagata et al 2005). Ecdysone is converted to 20-hydroxyecdysone, which acts on numerous target tissues and induces the expression of genes related to the molting process (Thummel 2002).…”

Section: Introductionmentioning

confidence: 99%

Localization of SNARE proteins in the brain and corpus allatum of Bombyx mori

Sasao

Uno

Kitagawa

et al. 2022

Histochem Cell Biol

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Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) comprise the core machinery that mediates membrane fusion. SNAREs, syntaxin, synaptosome-associated protein (SNAP), and synaptobrevin form a tight SNARE complex that brings the vesicle and plasma membranes together and is essential for membrane fusion. The cDNAs of SNAP-25, VAMP2, and Syntaxin 1A from Bombyx mori were inserted into a plasmid, transformed into Escherichia coli, and puri ed. We then produced antibodies against the SNAP-25, VAMP2, and Syntaxin 1A of Bombyx mori of rabbits and rats, which were used for immunohistochemistry. Immunohistochemistry results revealed that the expression of VAMP2 was restricted to neurons in the pars intercerebralis, dorsolateral protocerebrum, and central complex of the brain. SNAP-25 was restricted to neurons in the pars intercerebralis and the central complex of the brain. Syntaxin 1A was restricted to neurons in the pars intercerebralis and dorsolateral protocerebrum of the brain. SNAP-25 colocalizes with VAMP2 in the central complex and Syntaxin 1A colocalizes with bombyxin, which is an insect neuropeptide. These ndings suggest that SNARE proteins play important roles in membrane tra cking in the insect brain.

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Silk Moth Neuropeptide Hormones: Prothoracicotropic Hormone and Others

Cited by 19 publications

References 46 publications

Biomedical applications of silkworm ( Bombyx Mori ) proteins in regenerative medicine (a narrative review)

Biomedical applications of silkworm ( Bombyx Mori ) proteins in regenerative medicine (a narrative review)

Ligand-dependent responses of the silkworm prothoracicotropic hormone receptor, Torso, are maintained by unusual intermolecular disulfide bridges in the transmembrane region

Localization of SNARE proteins in the brain and corpus allatum of Bombyx mori

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