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Pancreatic duct-like cell line derived from pig embryonic stem cells: expression of uroplakin genes in pig pancreatic tissue. In Vitro Cell Dev Biol Anim 2019; 55:285-301. [PMID: 30868438 DOI: 10.1007/s11626-019-00336-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/12/2019] [Indexed: 02/04/2023]
Abstract
The isolation of a cell line, PICM-31D, with phenotypic characteristics like pancreatic duct cells is described. The PICM-31D cell line was derived from the previously described pig embryonic stem cell-derived exocrine pancreatic cell line, PICM-31. The PICM-31D cell line was morphologically distinct from the parental cells in growing as a monolayer rather than self-assembling into multicellular acinar-like structures. The PICM-31D cells were propagated for over a year at split ratios of 1:3 to 1:10 at each passage without change in phenotype or growth rate. Electron microscopy showed the cells to be a polarized epithelium of cuboidal cells joined by tight junction-like adhesions at their apical/lateral aspect. The cells contained numerous mucus-like secretory vesicles under their apical cell membrane. Proteomic analysis of the PICM-31D's cellular proteins detected MUC1 and MUC4, consistent with mucus vesicle morphology. Gene expression analysis showed the cells expressed pancreatic ductal cell-related transcription factors such as GATA4, GATA6, HES1, HNF1A, HNF1B, ONECUT1 (HNF6), PDX1, and SOX9, but little or no pancreas progenitor cell markers such as PTF1A, NKX6-1, SOX2, or NGN3. Pancreas ductal cell-associated genes including CA2, CFTR, MUC1, MUC5B, MUC13, SHH, TFF1, KRT8, and KRT19 were expressed by the PICM-31D cells, but the exocrine pancreas marker genes, CPA1 and PLA2G1B, were not expressed by the cells. However, the exocrine marker, AMY2A, was still expressed by the cells. Surprisingly, uroplakin proteins were prominent in the PICM-31D cell proteome, particularly UPK1A. Annexin A1 and A2 proteins were also relatively abundant in the cells. The expression of the uroplakin and annexin genes was detected in the cells, although only UPK1B, UPK3B, ANXA2, and ANXA4 were detected in fetal pig pancreatic duct tissue. In conclusion, the PICM-31D cell line models the mucus-secreting ductal cells of the fetal pig pancreas.
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Segretain D, Gilleron J, Bacro JN, Di Marco M, Carette D, Pointis G. Ultrastructural localization and distribution of Nardilysin in mammalian male germ cells. Basic Clin Androl 2016; 26:5. [PMID: 27051521 PMCID: PMC4820967 DOI: 10.1186/s12610-016-0032-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 03/10/2016] [Indexed: 11/16/2022] Open
Abstract
Background NRD convertase, also termed Nardilysin, is a Zn++ metalloendopeptidase that specifically cleaves the N-terminus of arginine and lysine residues into dibasic moieties. Although this enzyme was found located within the testis, its function in male reproduction is largely unknown. In addition, the precise distribution of this enzyme within germ cells remains to be determined. Methods To answer these questions, we developed an immuno-gold electron microscopy analysis to detect Nardilysin at ultrastructural level in mice. In addition, we performed a quantitative analysis of these gold particles to statistically estimate the distribution of Nardilysin in the different subcellular compartments of differentiating late spermatids/spermatozoa. Results Expression of Nardilysin in wild-type mice was restricted to germ cells and markedly increased during the last steps of spermiogenesis. In elongated spermatids, we found the enzyme mainly localized in the cytoplasm, more precisely associated with two microtubular structures, the manchette and the axoneme. No labelling was detected over the membranous organelles of the spermatids. To test whether this localization is dependent of the functional microtubules organization of the flagella, we analysed the localization into a specific mouse mutant ebo/ebo (ébouriffé) known to be sterile due to an impairment of the final organization of the flagellum. In the ebo/ebo, the enzyme was still localized over the microtubules of the axoneme and over the isolated cytoplasmic microtubules doublets. Quantification of gold particles in wild-type and mutant flagella revealed the specific association of the enzyme within the microtubular area of the axoneme. Conclusions The strong and specific accumulation of Nardilysin in the manchette and axoneme suggests that the enzyme probably contributes either to the establishment of these specific microtubular structures and/or to their functional properties.
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Affiliation(s)
- D Segretain
- UMR S 1147 Université Paris Descartes, 45 rue des Saint-Pères, 75006 Paris, France ; Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Versailles, 78000 France
| | - J Gilleron
- INSERM U 1065, Université Nice Sophia-Antipolis, 151 route Saint-Antoine de Ginestière BP 2 3194, 06204, Nice, cedex 3 France
| | - J N Bacro
- Institut de Mathématiques et de Modélisation de Montpellier (I3M), UMR CNRS 5149 Université Montpellier, CC 51; 4 place Eugène Bataillon 34095, Montpellier, cedex 5 France
| | - M Di Marco
- UMR S 1147 Université Paris Descartes, 45 rue des Saint-Pères, 75006 Paris, France ; Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Versailles, 78000 France
| | - D Carette
- UMR S 1147 Université Paris Descartes, 45 rue des Saint-Pères, 75006 Paris, France ; Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Versailles, 78000 France
| | - G Pointis
- INSERM U 1065, Université Nice Sophia-Antipolis, 151 route Saint-Antoine de Ginestière BP 2 3194, 06204, Nice, cedex 3 France
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Radichev IA, Maneva-Radicheva LV, Amatya C, Salehi M, Parker C, Ellefson J, Burn P, Savinov AY. Loss of Peripheral Protection in Pancreatic Islets by Proteolysis-Driven Impairment of VTCN1 (B7-H4) Presentation Is Associated with the Development of Autoimmune Diabetes. THE JOURNAL OF IMMUNOLOGY 2016; 196:1495-506. [PMID: 26773144 DOI: 10.4049/jimmunol.1403251] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 12/05/2015] [Indexed: 12/28/2022]
Abstract
Ag-specific activation of T cells is an essential process in the control of effector immune responses. Defects in T cell activation, particularly in the costimulation step, have been associated with many autoimmune conditions, including type 1 diabetes (T1D). Recently, we demonstrated that the phenotype of impaired negative costimulation, due to reduced levels of V-set domain-containing T cell activation inhibitor 1 (VTCN1) protein on APCs, is shared between diabetes-susceptible NOD mice and human T1D patients. In this study, we show that a similar process takes place in the target organ, as both α and β cells within pancreatic islets gradually lose their VTCN1 protein during autoimmune diabetes development despite upregulation of the VTCN1 gene. Diminishment of functional islet cells' VTCN1 is caused by the active proteolysis by metalloproteinase N-arginine dibasic convertase 1 (NRD1) and leads to the significant induction of proliferation and cytokine production by diabetogenic T cells. Inhibition of NRD1 activity, alternatively, stabilizes VTCN1 and dulls the anti-islet T cell responses. Therefore, we suggest a general endogenous mechanism of defective VTCN1 negative costimulation, which affects both lymphoid and peripheral target tissues during T1D progression and results in aggressive anti-islet T cell responses. This mechanism is tied to upregulation of NRD1 expression and likely acts in two synergistic proteolytic modes: cell-intrinsic intracellular and cell-extrinsic systemic. Our results highlight an importance of VTCN1 stabilization on cell surfaces for the restoration of altered balance of immune control during T1D.
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Affiliation(s)
- Ilian A Radichev
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and
| | - Lilia V Maneva-Radicheva
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and
| | - Christina Amatya
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and
| | - Maryam Salehi
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and
| | - Camille Parker
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and
| | - Jacob Ellefson
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and
| | - Paul Burn
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and
| | - Alexei Y Savinov
- The Sanford Project, Children's Health Research Center, Sanford Research, Sioux Falls, SD 57104; and Department of Pediatrics, University of South Dakota School of Medicine, Sioux Falls, SD 57105
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Cadel S, Darmon C, Pernier J, Hervé G, Foulon T. The M1 family of vertebrate aminopeptidases: role of evolutionarily conserved tyrosines in the enzymatic mechanism of aminopeptidase B. Biochimie 2014; 109:67-77. [PMID: 25530263 DOI: 10.1016/j.biochi.2014.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/11/2014] [Indexed: 01/15/2023]
Abstract
Aminopeptidase B (Ap-B), a member of the M1 family of Zn(2+)-aminopeptidases, removes basic residues at the NH2-terminus of peptides and is involved in the in vivo proteolytic processing of miniglucagon and cholecystokinin-8. M1 enzymes hydrolyze numerous different peptides and are implicated in many physiological functions. As these enzymes have similar catalytic mechanisms, their respective substrate specificity and/or catalytic efficiency must be based on subtle structural differences at or near the catalytic site. This leads to the hypothesis that each primary structure contains a consensus structural template, strictly necessary for aminopeptidase activity, and a specific amino acid environment localized in or outside the catalytic pocket that finely tunes the substrate specificity and catalytic efficiency of each enzyme. A multiple sequence alignment of M1 peptidases from vertebrates allowed to identify conserved tyrosine amino acids, which are members of this catalytic backbone. In the present work, site-directed mutagenesis and 3D molecular modeling of Ap-B were used to specify the role of four fully (Y281, Y229, Y414, and Y441) and one partially (Y409) conserved residues. Tyrosine to phenylalanine mutations allowed confirming the influence of the hydroxyl groups on the enzyme activity. These groups are implicated in the reaction mechanism (Y414), in substrate specificity and/or catalytic efficiency (Y409), in stabilization of essential amino acids of the active site (Y229, Y409) and potentially in the maintenance of its structural integrity (Y281, Y441). The importance of hydrogen bonds is verified by the Y229H substitution, which preserves the enzyme activity. These data provide new insights into the catalytic mechanism of Ap-B in the M1 family of aminopeptidases.
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Affiliation(s)
- Sandrine Cadel
- Sorbonne universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), FR 3631 UPMC-CNRS, BIOSIPE, BIOgenèse des SIgnaux PEptidiques, Paris, France.
| | - Cécile Darmon
- Sorbonne universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), FR 3631 UPMC-CNRS, BIOSIPE, BIOgenèse des SIgnaux PEptidiques, Paris, France.
| | - Julien Pernier
- Cytoskeleton Dynamics and Motility Group, Laboratoire d'Enzymologie et Biochimie Structurale [LEBS], UPR 3082 - CNRS, Gif-sur-Yvette, France.
| | - Guy Hervé
- Sorbonne universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), FR 3631 UPMC-CNRS, BIOSIPE, BIOgenèse des SIgnaux PEptidiques, Paris, France.
| | - Thierry Foulon
- Sorbonne universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), FR 3631 UPMC-CNRS, BIOSIPE, BIOgenèse des SIgnaux PEptidiques, Paris, France.
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5
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Pham VL, Gouzy-Darmon C, Pernier J, Hanquez C, Hook V, Beinfeld MC, Nicolas P, Etchebest C, Foulon T, Cadel S. Mutation in the substrate-binding site of aminopeptidase B confers new enzymatic properties. Biochimie 2011; 93:730-41. [DOI: 10.1016/j.biochi.2010.12.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 12/24/2010] [Indexed: 02/03/2023]
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Abstract
Brain damage as a result of hyperthermia or heat-stress has been the focus of attention in many areas of neuroscience in recent years. Heat-induced alterations in structural components of the central nervous system (CNS) will obviously also influence the relevant transmitter systems, which may be involved in a variety of different behaviors. Indeed, many studies have indicated that excitatory amino acids, and monoaminergic and peptidergic systems are affected during hyperthermia. This chapter will address past and current research on various neuropeptides that have been implicated in the consequences of hyperthermia and various other heat disorders. However, considering the large and even increasing number of identified neuroactive peptides, it is necessary to limit this chapter to a few peptides or peptide systems, which have received particular attention in relation to hyperthermia. Among these are the opioid peptides, the tachykinins, calcitonin gene-related peptide (CGRP), and peptides belonging to the angiotensin system. Most of these neuropeptides are not only affected by hyperthermia and abnormal alterations in the body temperature but also are involved in the endogenous mechanisms of regulating body temperature. This review does not endeavor to fully cover the field but it does aim to give the reader an idea of how various neuropeptides may be involved in the control of body heat and how peptidergic systems are affected during various thermal changes, including both immediate and long-term consequences.
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Affiliation(s)
- Fred Nyberg
- Department of Pharmaceutical Biosciences, Division of Biological Research on Drug Dependence, Uppsala University, S-751 24 Uppsala, Sweden.
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7
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Thompson MW, Archer ED, Romer CE, Seipelt RL. A conserved tyrosine residue of Saccharomyces cerevisiae leukotriene A4 hydrolase stabilizes the transition state of the peptidase activity. Peptides 2006; 27:1701-9. [PMID: 16597475 DOI: 10.1016/j.peptides.2006.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 02/21/2006] [Accepted: 02/22/2006] [Indexed: 11/25/2022]
Abstract
Saccharomyces cerevisiae leukotriene A4 hydrolase (LTA4H) is a bifunctional aminopeptidase/epoxide hydrolase and a member of the M1 family of metallopeptidases. In order to obtain a more thorough understanding of the aminopeptidase activity of the enzyme, two conserved tyrosine residues, Tyr244 and Tyr456, were altered to phenylalanine and the mutant proteins characterized by determining KM and kcat for various amino acid beta-naphthylamide substrates. While mutation of Tyr456 exhibited minimal effect on catalysis, mutation of Tyr244 caused an overall 25-100-fold reduction in catalytic activity for all substrates tested. Furthermore, LTA4H Y244F exhibited a 40-fold decrease in affinity for RB-3014, a transition state analog inhibitor, implicating Tyr244 in transition state stabilization.
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Affiliation(s)
- Michael W Thompson
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USA.
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8
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Chow KM, Csuhai E, Juliano MA, St Pyrek J, Juliano L, Hersh LB. Studies on the subsite specificity of rat nardilysin (N-arginine dibasic convertase). J Biol Chem 2000; 275:19545-51. [PMID: 10764809 DOI: 10.1074/jbc.m909020199] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The subsite specificity of rat nardilysin was investigated using fluorogenic substrates of the type 2-aminobenzoyl-GGX(1)X(2)RKX(3)GQ-ethylenediamine-2,4- dinitrophenyl, where P(2), P(2)', and P(3) residues were varied. (The nomenclature of Schechter and Berger (Schechter, I., and Berger, A. (1967) Biochem. Biophys. Res. Commun. 27, 157-162) is used where cleavage of a peptide occurs between the P(1) and P(1)' residues, and adjacent residues are designated P(2), P(3), P(2)', P(3)', etc.) There was little effect on K(m) among different residues at any of these positions. In contrast, residues at each position affected k(cat), with P(2) residues having the greatest effect. The S(3), S(2), and S(2)' subsites differed in their amino acid preference. Tryptophan and serine, which produced poor substrates at the P(2) position, were among the best P(2)' residues. The specificity at P(3) was generally opposite that of P(2). Residues at P(2), and to a lesser extent at P(3), influenced the cleavage site. At the P(2) position, His, Phe, Tyr, Asn, or Trp produced cleavage at the amino side of the first basic residue. In contrast, a P(2) Ile or Val produced cleavage between the dibasic pair. Other residues produced intermediate effects. The pH dependence for substrate binding showed that the enzyme prefers to bind a protonated histidine. A comparison of the effect of arginine or lysine at the P(1)' or P(1) position showed that there is a tendency to cleave on the amino side of arginine and that this cleavage produces the highest k(cat) values.
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Affiliation(s)
- K M Chow
- Department of Biochemistry and Mass Spectrometry Facility, University of Kentucky, Lexington, Kentucky 40563-0298, USA
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9
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Csuhai E, Juliano MA, Pyrek JS, Harms AC, Juliano L, Hersh LB. New fluorogenic substrates for N-arginine dibasic convertase. Anal Biochem 1999; 269:149-54. [PMID: 10094786 DOI: 10.1006/abio.1999.4033] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
N-Arginine dibasic (NRD) convertase is a recently described peptidase capable of selectively cleaving peptides between paired basic residues. The characterization of this unique peptidase has been hindered by the fact that no facile assay procedure has been available. Here we report the development of a rapid and sensitive assay for NRD convertase, based on the utilization of two new internally quenched fluorogenic peptides: Abz-GGFLRRVGQ-EDDnp and Abz-GGFLRRIQ-EDDnp. These peptides contain the fluorescent 2-aminobenzoyl moiety that is quenched in the intact peptide by a 2, 4-dinitrophenyl moiety. Cleavage by NRD convertase at the Arg-Arg sequence results in an increase of fluorescence. NRD convertase cleaves these peptides efficiently and with high specificity as observed by both HPLC and fluorescence spectroscopy. The rate of hydrolysis of the fluorogenic substrates is proportional to enzyme concentration, and obeys Michaelis-Menten kinetics. The kinetic parameters for the fluorescent peptides (Km values of approximately 1.0 microM, and Vmax values of approximately 1 microM/(min. mg) are similar to those obtained with peptide hormones as substrates.
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Affiliation(s)
- E Csuhai
- Department of Biochemistry, University of Kentucky, Lexington, Kentucky 40536-0084, USA
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10
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Jai-nhuknan J, Cassady CJ. Negative ion postsource decay time-of-flight mass spectrometry of peptides containing acidic amino acid residues. Anal Chem 1998; 70:5122-8. [PMID: 9868910 DOI: 10.1021/ac980577n] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acidic peptides have been studied by negative ion postsource decay (PSD) matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The peptides contained from 5 to 16 residues and were chosen on the basis of their patterns of the acidic residues. Using typical MALDI sample preparation techniques employing an acidic matrix, gastrin I (1-14), and epidermal mitosis inhibiting pentapeptide yielded much larger deprotonated ion signals, [M - H]-, than protonated ions, [M + H]+. This may be due to their absence of basic residues, coupled with their arrays of acidic residues. The PSD fragmentation of the peptide negative ions showed that an array of acidic residues, as in gastrin I (1-14), yielded simple spectra containing mainly backbone cleavage ions from the C-terminus. Hirudin (54-65), which contains two sets of two consecutive Glu residues, and fibrinopeptide A and fibrinopeptide B, with isolated acidic residues, also showed backbone cleavages as common fragment ions. In addition, the two sets of isolated consecutive amino acid residues in Cys(Bzl)84-CD4 (81-92) and hirudin (54-56) yielded internal ions from the cleavages at the (O=C)-NH bond between the acidic residues. Also observed were ions with unique side chain losses, such as the loss of C6H4O from a tyrosine residue and SCH2C6H5 and CH2C6H5 from a benzylated cysteine residue. Compared to the positive mode, the negative-ion PSD yielded fewer fragments which usually involved only one type of backbone cleavage (e.g., [Yn - H2O]-). These simple spectra aided interpretation. Overall, the acidic peptides studied yielded negative ion PSD spectra that were useful for peptide sequencing.
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Affiliation(s)
- J Jai-nhuknan
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, USA
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Abstract
It is generally accepted that sudden infant death syndrome (SIDS) victims fail to survive relatively minor stress in infancy. My hypothesis is that failure to orchestrate the endocrine response in stress leads to excessive release of neutral-endopeptidase-sensitive peptide substrates that enhance lethality. The 'quick zinc' response Reid recorded in livestock with circulatory shock is described. It is concluded that the failure to mount an endocrine response leads to SIDS.
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Balogh A, Cadel S, Foulon T, Picart R, Der Garabedian A, Rousselet A, Tougard C, Cohen P. Aminopeptidase B: a processing enzyme secreted and associated with the plasma membrane of rat pheochromocytoma (PC12) cells. J Cell Sci 1998; 111 ( Pt 2):161-9. [PMID: 9405297 DOI: 10.1242/jcs.111.2.161] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aminopeptidase B (Ap-B) is a Zn2+-dependent exopeptidase which selectively removes Arg and/or Lys residues from the N terminus of several peptide substrates. Isolated and characterized from rat testes, this ubiquitous enzyme may participate in the final stages of precursor processing mechanisms. To test this hypothesis, we have investigated the secretion and subcellular localization of this enzyme in a rat cell line of pheochromocytoma (PC12 cells). By using a combination of biochemical and immunocytochemical methods, the following observations were made: (i) the level of aminopeptidase B detectable in the cell culture medium increased with time; (ii) 8-bromo-adenosine 3′-5′-cyclic monophosphate and the Ca2+ ionophore A23187 both stimulated enzyme liberation in the culture medium; (iii) brefeldin A, an inhibitor of vesicular transport from the endoplasmic reticulum to the Golgi apparatus, decreased enzyme secretion in a time-dependent manner; (iv) whereas nocodazole, a microtubule depolymerizing agent, inhibited enzyme secretion, cytochalasin D, a microfilament disruption agent, had no effect on released aminopeptidase B level; (v) immunofluorescence demonstrated the presence of aminopeptidase B in the Golgi apparatus; (vi) immunofluorescence, electron microscopy and tests of enzyme activity on intact cells showed an association of the peptidase with the external face of the plasma membrane. Together these data strongly argued in favour of the enzyme secretion by PC12 cells. It is concluded that aminopeptidase B may participate in processing events occurring either during its intracellular transport along the secretory pathway or at the plasma membrane level, or both.
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Affiliation(s)
- A Balogh
- Unite de Recherche Associee au Centre National de la Recherche Scientifique 1682, Universite Pierre et Marie Curie, Paris, France
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Cadel S, Foulon T, Viron A, Balogh A, Midol-Monnet S, Noël N, Cohen P. Aminopeptidase B from the rat testis is a bifunctional enzyme structurally related to leukotriene-A4 hydrolase. Proc Natl Acad Sci U S A 1997; 94:2963-8. [PMID: 9096329 PMCID: PMC20305 DOI: 10.1073/pnas.94.7.2963] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
An aminopeptidase B (Ap-B) was previously purified to homogeneity from rat testis extracts and characterized. In the present work, by using oligonucleotides selected on the basis of partial amino acid microsequences of pure Ap-B and PCR techniques, the nucleotide sequence of a 2.2-kb cDNA was obtained. The deduced amino acid sequence corresponds to a 648-residue protein (72.3 kDa) containing the canonical "HEXXHX18E" signature, which allowed its classification as a member of the M1 family of metallopeptidases. It exhibits 33% identity and 48% similarity with leukotriene-A4 hydrolase, a relation further supported by the capacity of Ap-B to hydrolyze leukotriene A4. Both enzymes also were closely related to a partially sequenced protein from Dictyostelium discoideum, which might constitute the putative common ancestor of either aminopeptidase or epoxide hydrolase, or both. Ap-B and its mRNA were detected in the germ line and in the Sertoli and peritubular cells of the seminiferous tubules. Because the enzyme was found in the medium conditioned by spermatocytes and spermatids and in the acrosome during spermatozoa formation, together these observations suggested an involvement of this exometallopeptidase in the secretory pathway. It is concluded that this ubiquitous enzyme may be involved in multiple processing mechanisms.
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Affiliation(s)
- S Cadel
- Unité de Recherche Associée au Centre National de la Recherche Scientifique 1682, Université Pierre et Marie Curie, Paris, France
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Chesneau V, Prat A, Segretain D, Hospital V, Dupaix A, Foulon T, Jégou B, Cohen P. NRD convertase: a putative processing endoprotease associated with the axoneme and the manchette in late spermatids. J Cell Sci 1996; 109 ( Pt 11):2737-45. [PMID: 8937991 DOI: 10.1242/jcs.109.11.2737] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
N-arginine dibasic convertase is a novel metalloendopeptidase which selectively cleaves at the N terminus of arginine residues in paired basic amino acids. Although present in brain and several other tissues, NRD convertase is particularly abundant in testis, where its expression appeared to be restricted to germ cells. Low levels of both mRNA and its corresponding protein were detected early in spermatogenesis. However, a marked accumulation of the protein was observed during late steps (14 to 19) of spermiogenesis. By electron microscopy, the NRD convertase immunoreactivity was localized in the cytoplasm of elongating and elongated spermatids, with a noticeable concentration at the level of two microtubular structures, i.e. the manchette and the axoneme. These observations strongly support the hypothesis that NRD convertase is involved in processing events potentially associated with the morphological transformations occurring during spermiogenesis.
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Affiliation(s)
- V Chesneau
- Laboratoire de Biochimie des Signaux Régulateurs Cellulaires et Moléculaires, Université Pierre et Marie Curie, Paris, France
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