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Thesbjerg MN, Sundekilde UK, Poulsen NA, Larsen LB, Nielsen SDH. A novel proteomic approach for the identification and relative quantification of disulfide-bridges in the human milk proteome. J Proteomics 2024; 301:105194. [PMID: 38723850 DOI: 10.1016/j.jprot.2024.105194] [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: 11/29/2023] [Revised: 04/26/2024] [Accepted: 05/05/2024] [Indexed: 05/13/2024]
Abstract
This study explores the disulfide bridges present in the human milk proteome by a novel approach permitting both positional identification and relative quantification of the disulfide bridges. Human milk from six donors was subjected to trypsin digestion without reduction. The digested human milk proteins were analyzed by nanoLC-timsTOF Pro combined with data analysis using xiSEARCH. A total of 85 unique disulfide bridges were identified in 25 different human milk proteins. The total relative abundance of disulfide bridge-containing peptides constituted approximately 5% of the total amount of tryptic-peptides. Seven inter-molecular disulfide bridges were identified between either α-lactalbumin and lactotransferrin (5) or αS1-casein and κ-casein (2). All cysteines involved in the observed disulfide bridges of α-lactalbumin and lactotransferrin were mapped onto protein models using AlphaFold2 Multimer to estimate the length of the observed disulfide bridges. The lengths of the disulfide bridges of lactotransferrin indicate a potential for multi- or poly-merization of lactotransferrin. The high number of intramolecular lactotransferrin disulfide bridges identified, suggests that these are more heterogeneous than previously presumed. SIGNIFICANCE: Disulfide-bridges in the human milk proteome are an often overseen post-transaltional modification. Thus, mapping the disulfide-bridges, their positions and relative abundance, are valuable new knowledge needed for an improved understanding of human milk protein behaviour. Although glycosylation and phosphorylation have been described, even less information is available on the disulfide bridges and the disulfide-bridge derived protein complexes. This is important for future work in precision fermentation for recombinant production of human milk proteins, as this will highlight which disulfide-bridges are naturally occouring in human milk proteins. Further, this knowledge would be of value for the infant formula industry as it provides more information on how to humanize bovine-milk based infant formula. The novel method developed here can be broadly applied in other biological systems as the disulfid-brigdes are important for the structure and functionality of proteins.
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Affiliation(s)
- Martin Nørmark Thesbjerg
- Department of Food Science, Aarhus University, Agro Food Park 48, DK-8200 Aarhus N, Denmark; Sino-Danish College (SDC), University of Chinese Academy of Science, Huairou District, Beijing 101408, China.
| | | | - Nina Aagaard Poulsen
- Department of Food Science, Aarhus University, Agro Food Park 48, DK-8200 Aarhus N, Denmark
| | - Lotte Bach Larsen
- Department of Food Science, Aarhus University, Agro Food Park 48, DK-8200 Aarhus N, Denmark
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Zhu J, Lin YH, Dingess KA, Mank M, Stahl B, Heck AJR. Quantitative Longitudinal Inventory of the N-Glycoproteome of Human Milk from a Single Donor Reveals the Highly Variable Repertoire and Dynamic Site-Specific Changes. J Proteome Res 2020; 19:1941-1952. [PMID: 32125861 PMCID: PMC7252941 DOI: 10.1021/acs.jproteome.9b00753] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Protein N-glycosylation on human milk proteins assists in protecting an infant's health and functions among others as competitive inhibitors of pathogen binding and immunomodulators. Due to the individual uniqueness of each mother's milk and the overall complexity and temporal changes of protein N-glycosylation, analysis of the human milk N-glycoproteome requires longitudinal personalized approaches, providing protein- and N-site-specific quantitative information. Here, we describe an automated platform using hydrophilic-interaction chromatography (HILIC)-based cartridges enabling the proteome-wide monitoring of intact N-glycopeptides using just a digest of 150 μg of breast milk protein. We were able to map around 1700 glycopeptides from 110 glycoproteins covering 191 glycosites, of which 43 sites have not been previously reported with experimental evidence. We next quantified 287 of these glycopeptides originating from 50 glycoproteins using a targeted proteomics approach. Although each glycoprotein, N-glycosylation site, and attached glycan revealed distinct dynamic changes, we did observe a few general trends. For instance, fucosylation, especially terminal fucosylation, increased across the lactation period. Building on the improved glycoproteomics approach outlined above, future studies are warranted to reveal the potential impact of the observed glycosylation microheterogeneity on the healthy development of infants.
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Affiliation(s)
- Jing Zhu
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands.,Beijing Institute of Nutritional Resources, 100069 Beijing, China
| | - Yu-Hsien Lin
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Kelly A Dingess
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Marko Mank
- Danone Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, The Netherlands
| | - Bernd Stahl
- Danone Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, The Netherlands.,Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, 3584 CG Utrecht, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands.,Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Casein and Peptides Derived from Casein as Antileukaemic Agents. JOURNAL OF ONCOLOGY 2019; 2019:8150967. [PMID: 31582978 PMCID: PMC6754885 DOI: 10.1155/2019/8150967] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/20/2019] [Accepted: 08/04/2019] [Indexed: 12/20/2022]
Abstract
Milk is a heterogeneous lacteal secretion mixture of numerous components that exhibit a wide variety of chemical and functional activities. Casein, the main protein in milk, is composed of α-, β-, and κ-caseins, each of which is important for nutritional value and for promoting the release of cytokines, also are linked to the regulation of haematopoiesis and immune response and inhibit the proliferation and induce the differentiation of leukaemia cells. It has been shown that the digestive process of caseins leads to the release of bioactive peptides that are involved in the regulation of blood pressure and the inhibition or activation of the immune response by serving as agonists or antagonists of opioid receptors, thus controlling the expression of genes that exert epigenetic control. Later, they bind to opioid receptor, block nuclear factor κ-beta, increase the redox potential, and reduce oxidative stress and the pro-inflammatory agents that favour an antioxidant and anti-inflammatory environment. Therefore, the bioactive peptides of casein could be compounds with antileukaemia potential. This review provides a summary of current knowledge about caseins and casein peptides on the immune system as well as their roles in the natural defence against the development of leukaemia and as relevant epigenetic regulators that can help eradicate leukaemia.
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Ryskaliyeva A, Henry C, Miranda G, Faye B, Konuspayeva G, Martin P. Alternative splicing events expand molecular diversity of camel CSN1S2 increasing its ability to generate potentially bioactive peptides. Sci Rep 2019; 9:5243. [PMID: 30918277 PMCID: PMC6437144 DOI: 10.1038/s41598-019-41649-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 03/14/2019] [Indexed: 02/08/2023] Open
Abstract
In a previous study on camel milk from Kazakhstan, we reported the occurrence of two unknown proteins (UP1 and UP2) with different levels of phosphorylation. Here we show that UP1 and UP2 are isoforms of camel αs2-CN (αs2-CNsv1 and αs2-CNsv2, respectively) arising from alternative splicing events. First described as a 178 amino-acids long protein carrying eight phosphate groups, the major camel αs2-CN isoform (called here αs2-CN) has a molecular mass of 21,906 Da. αs2-CNsv1, a rather frequent (35%) isoform displaying a higher molecular mass (+1,033 Da), is present at four phosphorylation levels (8P to 11P). Using cDNA-sequencing, αs2-CNsv1 was shown to be a variant arising from the splicing-in of an in-frame 27-nucleotide sequence encoding the nonapeptide ENSKKTVDM, for which the presence at the genome level was confirmed. αs2-CNsv2, which appeared to be present at 8P to 12P, was shown to include an additional decapeptide (VKAYQIIPNL) revealed by LC-MS/MS, encoded by a 3′-extension of exon 16. Since milk proteins represent a reservoir of biologically active peptides, the molecular diversity generated by differential splicing might increase its content. To evaluate this possibility, we searched for bioactive peptides encrypted in the different camel αs2-CN isoforms, using an in silico approach. Several peptides, putatively released from the C-terminal part of camel αs2-CN isoforms after in silico digestion by proteases from the digestive tract, were predicted to display anti-bacterial and antihypertensive activities.
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Affiliation(s)
- Alma Ryskaliyeva
- INRA, UMR GABI, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Céline Henry
- INRA, MICALIS Institute, Plateforme d'Analyse Protéomique Paris Sud-Ouest (PAPPSO), Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Guy Miranda
- INRA, UMR GABI, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Bernard Faye
- CIRAD, UMR SELMET, 34398, Montpellier Cedex 5, France
| | - Gaukhar Konuspayeva
- Al-Farabi Kazakh National University, Biotechnology department, 050040, Almaty, Kazakhstan
| | - Patrice Martin
- INRA, UMR GABI, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
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Trujillo A, Jordana J, Guamis B, Serradilla J, Amills M. Revisión: E1 polimorfismo del gen de la caseina αs1 caprina y su efecto sobre la producción, la composición y las propiedades tecnológicas de la leche y sobre la fabricación y la maduración del queso. FOOD SCI TECHNOL INT 2016. [DOI: 10.1177/108201329800400401] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The caprine α s1-casein gene displays a high degree of polymorphism, with eight different protein variants described up to date. The rate of synthesis of the mature protein is closely linked to the caprine αs1-casein genotype. There are three variants which are associated to high αs1-casein content in milk (A, B, and C), one to an intermediate content (E), three to a low content (D, F, and G) and one to a null content (O). During the last few years studies of goat milk protein polymorphism have gained renewed interest, as the ocurrence of certain milk protein genetic variants is correlated with the composititon of milk and also with some milk processing parameters. For instance, analyses of the physicochemical properties of milk from goats homozy gous for the three main α s1-casein alleles (A, E, F) confirm the effects of the genotypes on the percentage of casein and fat, and shows significant effects on the diameter of the micelles and their calcium content. These characteristics seem to be associated with enhanced clotting of goat milk, cheese curd firmness, curd syneresis and overall cheese yield. The caprine αs1-casein gene constitutes a very attractive model for studying the regulation of the expression of the corresponding protein, and might also become a very powerful tool in improving the technolog ical properties of goat milk.
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Affiliation(s)
- A.J. Trujillo
- Unitat de Tecnologia dels Aliments. Centre Especial de Referència en Làctis. Facultat de Veterinària, Universitat Autònoma de Barcelona. Bellaterra 08193. Spain
| | - J. Jordana
- Unitat de Genètica i Millora. Facultat de Veterinària. Universitat Autònoma de Barcelona. Bellaterra 08193. Spain
| | - B. Guamis
- Unitat de Tecnologia dels Aliments. Centre Especial de Referència en Làctis. Facultat de Veterinària, Universitat Autònoma de Barcelona. Bellaterra 08193. Spain
| | - J.M. Serradilla
- Departamento de Producción Animal. Escuela Técnica Superior de Ingenieros Agrónomos y de Montes., Universidad de Córdoba. Córdoba 14080. Spain
| | - M. Amills
- Unitat de Genètica i Millora. Facultat de Veterinària. Universitat Autònoma de Barcelona. Bellaterra 08193. Spain
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Pauciullo A, Erhardt G. Molecular Characterization of the Llamas (Lama glama) Casein Cluster Genes Transcripts (CSN1S1, CSN2, CSN1S2, CSN3) and Regulatory Regions. PLoS One 2015; 10:e0124963. [PMID: 25923814 PMCID: PMC4414411 DOI: 10.1371/journal.pone.0124963] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/19/2015] [Indexed: 11/19/2022] Open
Abstract
In the present paper, we report for the first time the characterization of llama (Lama glama) caseins at transcriptomic and genetic level. A total of 288 casein clones transcripts were analysed from two lactating llamas. The most represented mRNA populations were those correctly assembled (85.07%) and they encoded for mature proteins of 215, 217, 187 and 162 amino acids respectively for the CSN1S1, CSN2, CSN1S2 and CSN3 genes. The exonic subdivision evidenced a structure made of 21, 9, 17 and 6 exons for the αs1-, β-, αs2- and κ-casein genes respectively. Exon skipping and duplication events were evidenced. Two variants A and B were identified in the αs1-casein gene as result of the alternative out-splicing of the exon 18. An additional exon coding for a novel esapeptide was found to be cryptic in the κ-casein gene, whereas one extra exon was found in the αs2-casein gene by the comparison with the Camelus dromedaries sequence. A total of 28 putative phosphorylated motifs highlighted a complex heterogeneity and a potential variable degree of post-translational modifications. Ninety-six polymorphic sites were found through the comparison of the lama casein cDNAs with the homologous camel sequences, whereas the first description and characterization of the 5'- and 3'-regulatory regions allowed to identify the main putative consensus sequences involved in the casein genes expression, thus opening the way to new investigations -so far- never achieved in this species.
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Affiliation(s)
- Alfredo Pauciullo
- Department of Agricultural, Forest and Food Sciences, University of Torino, Grugliasco, Italy
- Institute for Animal Breeding and Genetics, Justus Liebig University, Gießen, Germany
| | - Georg Erhardt
- Institute for Animal Breeding and Genetics, Justus Liebig University, Gießen, Germany
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7
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Biochemical and molecular characterization of polymorphisms of αs1-casein in Sudanese camel (Camelus dromedarius) milk. Int Dairy J 2013. [DOI: 10.1016/j.idairyj.2012.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Boumahrou N, Bevilacqua C, Beauvallet C, Miranda G, Andrei S, Rebours E, Panthier JJ, Bellier S, Martin P. Evolution of major milk proteins in Mus musculus and Mus spretus mouse species: a genoproteomic analysis. BMC Genomics 2011; 12:80. [PMID: 21276224 PMCID: PMC3048548 DOI: 10.1186/1471-2164-12-80] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 01/28/2011] [Indexed: 11/10/2022] Open
Abstract
Background Due to their high level of genotypic and phenotypic variability, Mus spretus strains were introduced in laboratories to investigate the genetic determinism of complex phenotypes including quantitative trait loci. Mus spretus diverged from Mus musculus around 2.5 million years ago and exhibits on average a single nucleotide polymorphism (SNP) in every 100 base pairs when compared with any of the classical laboratory strains. A genoproteomic approach was used to assess polymorphism of the major milk proteins between SEG/Pas and C57BL/6J, two inbred strains of mice representative of Mus spretus and Mus musculus species, respectively. Results The milk protein concentration was dramatically reduced in the SEG/Pas strain by comparison with the C57BL/6J strain (34 ± 9 g/L vs. 125 ± 12 g/L, respectively). Nine major proteins were identified in both milks using RP-HPLC, bi-dimensional electrophoresis and MALDI-Tof mass spectrometry. Two caseins (β and αs1) and the whey acidic protein (WAP), showed distinct chromatographic and electrophoresis behaviours. These differences were partly explained by the occurrence of amino acid substitutions and splicing variants revealed by cDNA sequencing. A total of 34 SNPs were identified in the coding and 3'untranslated regions of the SEG/Pas Csn1s1 (11), Csn2 (7) and Wap (8) genes. In addition, a 3 nucleotide deletion leading to the loss of a serine residue at position 93 was found in the SEG/Pas Wap gene. Conclusion SNP frequencies found in three milk protein-encoding genes between Mus spretus and Mus musculus is twice the values previously reported at the whole genome level. However, the protein structure and post-translational modifications seem not to be affected by SNPs characterized in our study. Splicing mechanisms (cryptic splice site usage, exon skipping, error-prone junction sequence), already identified in casein genes from other species, likely explain the existence of multiple αs1-casein isoforms both in SEG/Pas and C57BL/6J strains. Finally, we propose a possible mechanism by which the hallmark tandem duplication of a 18-nt exon (14 copies) may have occurred in the mouse genome.
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Affiliation(s)
- Nisrine Boumahrou
- INRA, UR1313 Génétique animale et Biologie intégrative UMR 1313, Equipe LGS, Jouy-en-Josas, France
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Vordenbäumen S, Braukmann A, Petermann K, Scharf A, Bleck E, von Mikecz A, Jose J, Schneider M. Casein α s1 is expressed by human monocytes and upregulates the production of GM-CSF via p38 MAPK. THE JOURNAL OF IMMUNOLOGY 2010; 186:592-601. [PMID: 21135174 DOI: 10.4049/jimmunol.1001461] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Caseins are major constituents of mammalian milks that are thought to be exclusively expressed in mammary glands and to function primarily as a protein source, as well as to ameliorate intestinal calcium uptake. In addition, proinflammatory and immunomodulatory properties have been reported for bovine caseins. Our aim was to investigate whether human casein α s1 (CSN1S1) is expressed outside the mammary gland and possesses immunomodulatory functions in humans as well. For this purpose, CSN1S1 mRNA was detected in primary human monocytes and CD4(+) and CD8(+) T cells, but not in CD19(+) B cells. CSN1S1 protein was traceable in supernatants of cultured primary human CD14(+) monocytes by ELISA. Similarly, CSN1S1 mRNA and protein were detected in the human monocytic cell lines HL60, U937, and THP1 but not in Mono Mac 6 cells. Moreover, permeabilized human monocytes and HL60 cells could be stained by immunofluorescence, indicating intracellular expression. Recombinant human CSN1S1 was bound to the surface of Mono Mac 6 cells and upregulated the expression of GM-CSF mRNA in primary human monocytes and Mono Mac 6 cells in a time- and concentration-dependent manner. A similar increase in GM-CSF protein was found in the culture supernatants. CSN1S1-dependent upregulation of GM-CSF was specifically blocked by the addition of the p38 MAPK inhibitor ML3403. Our results indicated that human CSN1S1 may possess an immunomodulatory role beyond its nutritional function in milk. It is expressed in human monocytes and stimulates the expression of the proinflammatory cytokine GM-CSF.
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Affiliation(s)
- Stefan Vordenbäumen
- Department of Endocrinology, Diabetology and Rheumatology, Institute of Pharmaceutical Chemistry, Heinrich Heine University, Düsseldorf, Germany.
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Matéos A, Miclo L, Mollé D, Dary A, Girardet JM, Gaillard JL. Equine αS1-casein: Characterization of alternative splicing isoforms and determination of phosphorylation levels. J Dairy Sci 2009; 92:3604-15. [DOI: 10.3168/jds.2009-2125] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Wu YC, Lin JS, Hwang CC. Structure−Activity Relationships of αS1-Casomorphin Using AM1 Calculations and Molecular Dynamics Simulations. J Phys Chem B 2007; 111:7377-83. [PMID: 17530883 DOI: 10.1021/jp070477y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper investigates the structure-activity relationships of alphaS1-casomorphin (alphaS1-CM) using AM1 calculations and molecular dynamics (MD) simulations. Previous studies have shown that this peptide has remarkable opioid actions, and not only has a high affinity toward all three subtypes (kappa1-kappa3) of the kappa-opioid sites, but also inhibits the proliferation of the T47D human breast cancer cell line. The systematic conformer search performed by the AM1 calculations is based on the torsional angles of the Val2-Pro3 (omega2) and Phe4-Pro5 (omega4) amide bonds. The AM1 results reveal that the alphaS1-CM conformers strongly favor the cis/cis pair of the omega2/omega4 amide bonds in the minimized energy state. Furthermore, the picture of these stable conformers is found to be a strong interaction of the coulomb's force between two terminuses. MD simulations are performed to investigate the features of both the structural stability and pharmacological activity of alphaS1-CM in aqueous solution. The simulation results reveal that the omega2/omega4 amide bonds favor the cis/cis status in the stable state. Furthermore, the pharmacophoric distance between two aromatic rings is found to be 5.0 approximately 5.4A. The chi1 rotamers of the Tyr and Phe residues show a preference for gauche (-) and trans, respectively. The side chain rotamers of alphaS1-CM are competed to those of other opioid ligands with a known potency and selectivity for delta- and mu-opioid receptors. Finally, we address a likely kappa pharmacophore model compared to the delta pharmacophore model.
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Affiliation(s)
- Yng-Ching Wu
- Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan
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13
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Miclo L, Girardet JM, Egito AS, Mollé D, Martin P, Gaillard JL. The primary structure of a low-Mr multiphosphorylated variant ofβ-casein in equine milk. Proteomics 2007; 7:1327-35. [PMID: 17366489 DOI: 10.1002/pmic.200600683] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Highly phosphorylated casein with a low molecular mass was isolated from Haflinger mare's milk by RP-HPLC. It accounts for 4.0% of the casein content. Its mass was determined by LC-ESI-MS before and after treatment by alkaline phosphatase. The molecular mass found for the apo-form (10,591 +/- 2 Da) is in agreement with its primary structure, which was established by ESI-MS/MS from tryptic peptides. It appeared that this short protein (94 amino acid residues) is an internally truncated form of the full-length equine beta-casein (226 residues). This low-Mr variant of equine beta-casein displays a large deletion (residues 50-181), due to a cryptic splice site usage occurring within exon 7 during the course of primary transcripts processing. The phosphorylation pattern of this equine beta-casein variant was investigated by LC-ESI-MS and 2-DE. Seven phosphorylation forms were identified with one to seven phosphate groups with pIs ranging between 4.67 and 4.01. The major isoforms carry five and six phosphate groups.
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Affiliation(s)
- Laurent Miclo
- Unité de Recherche sur l'Animal et les Fonctionnalités des Produits Animaux , U.C. L'Institut National de la Recherche Agronomique 340, Nancy-Université, Vandoeuvre-lès-Nancy, France.
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Lenasi T, Peterlin BM, Dovc P. Distal regulation of alternative splicing by splicing enhancer in equine beta-casein intron 1. RNA (NEW YORK, N.Y.) 2006; 12:498-507. [PMID: 16431989 PMCID: PMC1383587 DOI: 10.1261/rna.7261206] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Accepted: 12/01/2005] [Indexed: 05/06/2023]
Abstract
The complexity of cotranscriptional splicing is reflected in the coordinated interplay between various cis-elements and transacting factors. In this report, we demonstrated that a cis-element in intron 1 of the equine beta-casein gene (intronic splicing enhancer 1, ISE1) increases the inclusion of all weak exons in its pre-mRNA. The ISE1 also functioned on a hybrid transcript, which was transcribed from the alpha-globin promoter, where it increased the inclusion of the human fibronectin EDA exon and the beta-casein exon 5. The region of ISE1 necessary for its function included the same sequence as is found in some exonic splicing enhancers. Since the ISE1 influenced the splicing of the entire transcript from intron 1, we propose a model for the cotranscriptional splicing of beta-casein mRNA, where the 5' end of the growing transcript remains associated with the C-terminal domain of RNA polymerase II. Thus, the ISE1 remains in close proximity to the mRNA exit groove throughout transcription and influences all weak exons as soon as they are copied.
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Affiliation(s)
- Tina Lenasi
- University of Ljubljana, Biotechnical Faculty, Department of Animal Science, Groblje, Slovenia.
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15
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Sørensen ES, Møller L, Vinther M, Petersen TE, Rasmussen LK. The phosphorylation pattern of human alphas1-casein is markedly different from the ruminant species. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:3651-5. [PMID: 12919330 DOI: 10.1046/j.1432-1033.2003.03755.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Caseins are highly phosphorylated milk proteins assembled in large colloidal structures termed micelles. In the milk of ruminants, alphas1-casein has been shown to be extensively phosphorylated. In this report we have determined the phosphorylation pattern of human alphas1-casein by a combination of matrix-assisted laser desorption mass spectrometry and amino acid sequence analysis. Three phosphorylation variants were identified. A nonphosphorylated form, a variant phosphorylated at Ser18 and a variant phosphorylated at Ser18 and Ser26. Both phosphorylation sites are located in the amino acid recognition sequence of the mammary gland casein kinase. Notably, no phosphorylations were observed in the conserved region covering residues Ser70-Glu78, which is extensively phosphorylated in the ruminant alphas1-caseins.
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Affiliation(s)
- Esben S Sørensen
- Protein Chemistry Laboratory, Department of Molecular Biology, University of Aarhus, Denmark.
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Rijnkels M. Multispecies comparison of the casein gene loci and evolution of casein gene family. J Mammary Gland Biol Neoplasia 2002; 7:327-45. [PMID: 12751895 DOI: 10.1023/a:1022808918013] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Caseins, the major milk proteins, are present in a genomic cluster spanning 250-350 kb. The divergence at the coding level between human, rodent, and cattle sequences is rather extensive for most of the genes in this region. Nevertheless, comparative analysis of genomic sequences harboring the casein gene cluster region of these species (with equal evolutionary distances 79-88 Myr) shows that the organization and orientation of the genes is highly conserved. The conserved gene structure indicates that the molecular diversity of the casein genes is achieved through variable use of exons in different species and high evolutionary divergence. Comparative analysis also revealed the presence within two species of uncharacterized casein family members and ruled out the previously held notion that another gene family, located in this region, is primate-specific. Several other new genes as well as conserved noncoding sequences with potential regulatory functions were identified. All genes identified in this region are, or are predicted to be, secreted proteins involved in mineral homeostasis, nutrition, and/or host defense, and are mostly expressed in the mammary and/or salivary glands. These observations suggest a possible common ancestry for the genes in this region.
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Affiliation(s)
- Monique Rijnkels
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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Abstract
Milk is mammalian characteristic and is of particular importance for humans: Mother's milk or its substitutes from cows' milk are absolutely essential nutriments for the neonate and cows' milk also represents a basic foodstuff for adults. However, in addition to their well-known nutritive role, milk constituents apparently are also able to carry specific information from the milk producer's to the milk receiver's organism: Thus, a number of milk protein fragments has been shown to behave like opioid receptor ligands able to address opioidergic systems in the adult's or in the neonate's organism. With respect to the proteins, which they are derived off these peptides have been named alpha-casein exorphins or casoxin D (alpha-casein), beta-casomorphins or beta-casorphin (beta-casein), casoxin or casoxin A, B, or C (k-casein), alpha-lactorphins (alpha-lactalbumin), beta-lactorphin (beta-lactoglobulin) or lactoferroxins (lactoferrin). Only casoxins and lactoferroxins display antagonistic properties; the other peptides behave like opioid receptor agonists. Most of the information available so far has been collected about beta-casomorphins. These peptides obviously can be released from beta-casein in the adult's or in the neonate's organism, where they might elicit opioid effects in the frame of a regulatory role as "food hormones". Several synthetic beta-casomorphin derivatives have been shown to be highly specific and potent mu-type opioid receptor ligands which frequently have been used as standard tools in opioid research.
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Affiliation(s)
- H Teschemacher
- Rudolf-Buchheim-Institut für Pharmakologie, Justus-Liebig-Universität, Giessen, Germany
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18
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Abstract
The caseins comprise the major protein component of milk of most mammals and are secreted as micelles that also carry high concentrations of calcium. They are phosphoproteins that represent the products of four genes, equivalent to those that encode the bovine alpha s1, alpha s2, beta, and kappa-caseins. There is considerable variation in the relative proportions of the particular caseins across species. The primary sequences of the alpha s1, alpha s2, and beta-caseins also show considerable species variation consistent with rapidly evolving genes that are proposed to have a common precursor. In contrast, the kappa-caseins exhibit features that demonstrate a separate origin and function where they are proposed to stabilise the micelle structure. This review focuses on comparative aspects of the caseins across a number of species for which information is now available.
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Affiliation(s)
- M R Ginger
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Ginger MR, Piotte CP, Otter DE, Grigor MR. Identification, characterisation and cDNA cloning of two caseins from the common brushtail possum (Trichosurus vulpecula)1. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1427:92-104. [PMID: 10082990 DOI: 10.1016/s0304-4165(99)00008-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Two major caseins have been isolated from the milk of the common brushtailed possum (Trichosurus vulpecula). These have been identified as alpha- and beta-casein on the basis of the similarity of their N-terminal sequences to those of the caseins of another marsupial (Macropus eugenii). Both proteins appear to exist in multiple forms. Possum alpha-casein is glycosylated mainly in the form of sialic acid residues and was shown by electrospray mass spectrometry to have multiply phosphorylated forms of three families with molecular masses 22700 and 23200 Da that may represent genetic variants. Two-dimensional electrophoresis showed that beta-casein exists as a complex of five or six proteins of identical N-terminal sequence but differing pI. Electrospray mass spectrometry indicated that the beta-caseins also are multiply phosphorylated with masses between 32300 and 32600 Da. A subfamily with mass values 1530 greater was also detected. The patterns were not affected by stage of lactation and quantitative analysis of two-dimensional gels of whole milk shows that alpha- and beta-caseins are present at a constant ratio throughout lactation. cDNA clones for the possum alpha- and beta-caseins have been isolated from an early lactation mammary cDNA library and sequenced.
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Affiliation(s)
- M R Ginger
- Department of Biochemistry and Centre for Gene Research, University of Otago, Dunedin, New Zealand
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Rasmussen L, Johnsen L, Tsiora A, Sørensen E, Thomsen J, Nielsen N, Jakobsen H, Petersen T. Disulphide-linked caseins and casein micelles. Int Dairy J 1999. [DOI: 10.1016/s0958-6946(99)00063-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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FUJIWARA Y, MIWA M, SUZUKI T, UEDA M. A Comparative Study of the 5' Flanking Sequences of the .ALPHA.S1- and .BETA.-Casein Genes: Human and Other Mammalian Species. J Reprod Dev 1997. [DOI: 10.1262/jrd.43.333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Yoshihiro FUJIWARA
- YS New Technology Institute. Inc., 519 Shimoishibashi, Ishibashi-machi, Shimotsuga-gun, Tochigi 329-05, Japan
| | - Masami MIWA
- YS New Technology Institute. Inc., 519 Shimoishibashi, Ishibashi-machi, Shimotsuga-gun, Tochigi 329-05, Japan
| | - Takashige SUZUKI
- YS New Technology Institute. Inc., 519 Shimoishibashi, Ishibashi-machi, Shimotsuga-gun, Tochigi 329-05, Japan
| | - Masatsugu UEDA
- YS New Technology Institute. Inc., 519 Shimoishibashi, Ishibashi-machi, Shimotsuga-gun, Tochigi 329-05, Japan
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Kampa M, Loukas S, Hatzoglou A, Martin P, Martin PM, Castanas E. Identification of a novel opioid peptide (Tyr-Val-Pro-Phe-Pro) derived from human alpha S1 casein (alpha S1-casomorphin, and alpha S1-casomorphin amide). Biochem J 1996; 319 ( Pt 3):903-8. [PMID: 8920997 PMCID: PMC1217873 DOI: 10.1042/bj3190903] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A new casomorphin pentapeptide (alpha S1-casomorphin) has been isolated from the sequence of human alpha S1-casein [alpha S1-casein-(158-162)], with the sequence Tyr-Val-Pro-Phe-Pro. This peptide was found to bind with high affinity to all three subtypes of the kappa-opioid receptor (kappa 1-kappa 2). When amidated at the C-terminus, alpha S1-casomorphin amide binds to the delta- and kappa 3-opioid sites. Both alpha S1-casomorphin and its amide inhibit in a dose-dependent and reversible manner the proliferation of T47D human breast cancer cells. This anti-proliferative activity was greater for alpha S1-casomorphin, which was the most potent opioid in inhibiting T47D cell proliferation. In T47D breast cancer cells, other casomorphins have been found to bind to somatostatin receptors in addition to opioid sites. In contrast, alpha S1-casomorphin and its amide do not interact with somatostatin receptors in our system.
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Affiliation(s)
- M Kampa
- Laboratory of Experimental Endocrinology, University of Crete School of Medicine and University Hospital, Heraklion, Greece
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