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Yano Y, Fukuoka R, Maturana AD, Ohdachi SD, Kita M. Mammalian neurotoxins, Blarina paralytic peptides, cause hyperpolarization of human T-type Ca channel hCa v3.2 activation. J Biol Chem 2023; 299:105066. [PMID: 37468103 PMCID: PMC10493266 DOI: 10.1016/j.jbc.2023.105066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023] Open
Abstract
Among the rare venomous mammals, the short-tailed shrew Blarina brevicauda has been suggested to produce potent neurotoxins in its saliva to effectively capture prey. Several kallikrein-like lethal proteases have been identified, but the active substances of B. brevicauda remained unclear. Here, we report Blarina paralytic peptides (BPPs) 1 and 2 isolated from its submaxillary glands. Synthetic BPP2 showed mealworm paralysis and a hyperpolarization shift (-11 mV) of a human T-type Ca2+ channel (hCav3.2) activation. The amino acid sequences of BPPs were similar to those of synenkephalins, which are precursors of brain opioid peptide hormones that are highly conserved among mammals. However, BPPs rather resembled centipede neurotoxic peptides SLPTXs in terms of disulfide bond connectivity and stereostructure. Our results suggested that the neurotoxin BPPs were the result of convergent evolution as homologs of nontoxic endogenous peptides that are widely conserved in mammals. This finding is of great interest from the viewpoint of the chemical evolution of vertebrate venoms.
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Affiliation(s)
- Yusuke Yano
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Ryo Fukuoka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Andres D Maturana
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Satoshi D Ohdachi
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Masaki Kita
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
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Fricker LD, Margolis EB, Gomes I, Devi LA. Five Decades of Research on Opioid Peptides: Current Knowledge and Unanswered Questions. Mol Pharmacol 2020; 98:96-108. [PMID: 32487735 DOI: 10.1124/mol.120.119388] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 05/06/2020] [Indexed: 12/20/2022] Open
Abstract
In the mid-1970s, an intense race to identify endogenous substances that activated the same receptors as opiates resulted in the identification of the first endogenous opioid peptides. Since then, >20 peptides with opioid receptor activity have been discovered, all of which are generated from three precursors, proenkephalin, prodynorphin, and proopiomelanocortin, by sequential proteolytic processing by prohormone convertases and carboxypeptidase E. Each of these peptides binds to all three of the opioid receptor types (μ, δ, or κ), albeit with differing affinities. Peptides derived from proenkephalin and prodynorphin are broadly distributed in the brain, and mRNA encoding all three precursors are highly expressed in some peripheral tissues. Various approaches have been used to explore the functions of the opioid peptides in specific behaviors and brain circuits. These methods include directly administering the peptides ex vivo (i.e., to excised tissue) or in vivo (in animals), using antagonists of opioid receptors to infer endogenous peptide activity, and genetic knockout of opioid peptide precursors. Collectively, these studies add to our current understanding of the function of endogenous opioids, especially when similar results are found using different approaches. We briefly review the history of identification of opioid peptides, highlight the major findings, address several myths that are widely accepted but not supported by recent data, and discuss unanswered questions and future directions for research. SIGNIFICANCE STATEMENT: Activation of the opioid receptors by opiates and synthetic drugs leads to central and peripheral biological effects, including analgesia and respiratory depression, but these may not be the primary functions of the endogenous opioid peptides. Instead, the opioid peptides play complex and overlapping roles in a variety of systems, including reward pathways, and an important direction for research is the delineation of the role of individual peptides.
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Affiliation(s)
- Lloyd D Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
| | - Elyssa B Margolis
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
| | - Ivone Gomes
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
| | - Lakshmi A Devi
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
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Subirán N, Candenas L, Pinto FM, Cejudo-Roman A, Agirregoitia E, Irazusta J. Autocrine regulation of human sperm motility by the met-enkephalin opioid peptide. Fertil Steril 2012; 98:617-625.e3. [DOI: 10.1016/j.fertnstert.2012.05.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 05/23/2012] [Accepted: 05/23/2012] [Indexed: 01/29/2023]
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Cool DR, Jackson SB, Waddell KS. Structural Requirements for Sorting Pro-Vasopressin to the Regulated Secretory Pathway in a Neuronal Cell Line. OPEN NEUROENDOCRINOLOGY JOURNAL (ONLINE) 2008; 1:1-8. [PMID: 19830265 PMCID: PMC2760848 DOI: 10.2174/1876528900801010001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vasopressin is a peptide hormone normally secreted via the regulated secretory pathway in neuro-endocrine cells. In an effort to determine which region of vasopressin contains sufficient information for sorting, we created five constructs with the cDNA for vasopressin or regions of vasopressin in frame with the gene for green fluorescent protein (GFP). Fluorescence microscopy of Neuro-2a cells expressing the constructs revealed full-length vasopressin-GFP (VP-GFP), neurophysin-GFP (NP-GFP) and arginine-vasopressin/neurophysin-GFP (AN-GFP), were localized to punctate granules in the neurites and accumulated at the tips of neurites, characteristic of regulated secretory granules. These fusion proteins were secreted in a regulated manner as determined by pulse-chase labeling experiments. Two other chimeric proteins, signalpeptide-GFP and AVP-GFP were localized to a perinuclear region, characteristic of the endoplasmic reticulum. Pulse/chase [(35)S]labeling followed by immunoprecipitation using anti-GFP antibody indicated that these two fusion proteins were constitutively secreted. We conclude that the neurophysin region of pro-vasopressin contains information that is both sufficient and necessary for sorting GFP into the regulated secretory pathway.
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Affiliation(s)
- David R. Cool
- Boonshoft School of Medicine, Department of Pharmacology & Toxicology, Wright State University, Dayton, OH 45435
| | - Steven B. Jackson
- Boonshoft School of Medicine, Department of Pharmacology & Toxicology, Wright State University, Dayton, OH 45435
| | - Karen S. Waddell
- Boonshoft School of Medicine, Department of Pharmacology & Toxicology, Wright State University, Dayton, OH 45435
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Loh YP, Maldonado A, Zhang C, Tam WH, Cawley N. Mechanism of sorting proopiomelanocortin and proenkephalin to the regulated secretory pathway of neuroendocrine cells. Ann N Y Acad Sci 2002; 971:416-25. [PMID: 12438160 DOI: 10.1111/j.1749-6632.2002.tb04504.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proopiomelanocortin (POMC) and proenkephalin (PE) are synthesized at the endoplasmic reticulum and transported to the trans-Golgi network (TGN) where they are sorted and packaged into dense-core granules of the regulated secretory pathway (RSP). The mechanism of sorting POMC and PE to the RSP in neuroendocrine cells was investigated. Consensus sorting signals comprising two acidic residues and two hydrophobic residues exposed on the surface of N-POMC(1-26) and N-PE(1-32) were identified and shown to be sufficient and necessary for targeting POMC and PE to the RSP in PC12, Neuro2a, and AtT-20 cells. The acidic residues of these sorting signals bind specifically to basic residues on the sorting receptor membrane, carboxypeptidase E (CPE), to effect sorting to the RSP. Analysis of POMC and PE sorting in Neuro2a cells depleted of CPE by CPE antisense RNA, and Cpe(fat/fat) mouse pituitary cells lacking CPE showed missorting of both these molecules to the constitutive pathway in vivo. Thus, POMC and PE are sorted to the RSP at the TGN by a mechanism involving the interaction of a specific sorting signal on these molecules with the sorting receptor, CPE.
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Affiliation(s)
- Y Peng Loh
- Section on Cellular Neurobiology, Laboratory of Developmental Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Loh YP, Snell CR, Cool DR. Receptor-mediated targeting of hormones to secretory granules: role of carboxypeptidase E. Trends Endocrinol Metab 1997; 8:130-7. [PMID: 18406798 DOI: 10.1016/s1043-2760(97)00010-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Peptide hormones, neuropeptides, and other molecules such as the granins are specifically packaged into granules of the regulated secretory pathway and released in a calcium-dependent manner upon stimulation. Many of these molecules are synthesized as larger precursors (prohormones) that are processed to biologically active products within the granules. It has now become apparent that prohormones, proneuropeptides, and the granins contain conformation-dependent sorting signal motifs that facilitate their specific sorting and packaging into regulated secretory granules. Recently, a receptor to which these sorting signals bind has been identified as the membrane form of carboxypeptidase E (CPE) and localized to the Golgi apparatus, where sorting occurs, specifically at the trans-Golgi network. In this article, we review the evidence for a sorting signal-receptor-mediated mechanism for routing peptide hormones and prohormones to the regulated secretory granules. We also describe a mouse model, Cpe(fat), which has the CPE gene naturally mutated. Pituitary hormones were misrouted and secreted in an unregulated manner via the constitutive pathway in these Cpe(fat) mice, leading to endocrine disorders.
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Affiliation(s)
- Y P Loh
- Section on Cellular Neurobiology, Laboratory of Developmental Neurobiology, NICHD, National Institutes of Health, Bethesda, MD 20892, USA
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