title: Proteomic profiling of gill GSTs in Mytilus galloprovincialis from the North of Portugal and Galicia evidences variations at protein isoform level with a possible relation with water quality.
abstract: Glutathione transferases (GSTs) are key for xenobiotic detoxification at the molecular level across phyla. These enzymes are therefore likely to be part of the defence mechanisms used by marine organisms, such as mussels, that thrive in highly polluted environments. Taking this hypothesis into account, we used proteomics to characterize the profile of GSTs from the gills of marine mussel Mytilus galloprovincialis in order to discriminate natural mussel populations exposed to different levels of pollution. Samples were collected between Cabo Home (Spain) and Matosinhos (Portugal) covering a north-south transect of approximately 122 Km of the Atlantic Ocean along the Western Coast of the Iberian Peninsula. GSTs from mussel gills were extracted and purified by affinity chromatography with glutathione as the binding substrate to the solid medium. We studied the abundance of GST isoforms by two-dimensional gel electrophoresis and matrix assisted laser desorption/ionization-time of flight mass spectrometry and assessed total activity. Eleven putative individual GSTs from classes Mu, Pi and Sigma were identified by proteomics. Few variations were observed in total GST activity of post-mitochondrial samples between sampling sites, with animals from Matosinhos (polluted site) showing highest GST activity and Cabo Home (clean site) showing lowest. This contrasts with the increased number of differences in the individual GST isoforms. Each mussel population showed unique GST proteomic profiles. Based on the results we conclude that proteomics surpasses the conventional GST enzymatic activity method to discriminate natural mussel populations and has potential application in environmental monitoring. It is reasonable to suggest that the GST proteomic profiles observed may reflect differences in contamination levels.
authors.affiliation: Interdisciplinary Centre of Marine and Environmental Research, CIIMAR/CIMAR, Porto, Portugal.
authors.forename: Catarina C
authors.initials: CC
authors.lastname: Azevedo
authors.affiliation: Area of Toxicology, Faculty of Pharmacy, University of Sevilla, Seville, Spain.
authors.forename: Remédios
authors.initials: R
authors.lastname: Guzmán-Guillén
authors.affiliation: Interdisciplinary Centre of Marine and Environmental Research, CIIMAR/CIMAR, Porto, Portugal.
authors.forename: José C
authors.initials: JC
authors.lastname: Martins
authors.affiliation: Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal; Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Osório
authors.affiliation: Interdisciplinary Centre of Marine and Environmental Research, CIIMAR/CIMAR, Porto, Portugal; Department of Biology, Faculty of Sciences of the University of Porto, Porto, Portugal.
authors.forename: Vitor
authors.initials: V
authors.lastname: Vasconcelos
authors.affiliation: The Bioinformatics Centre, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Rute R
authors.initials: RR
authors.lastname: da Fonseca
authors.affiliation: Interdisciplinary Centre of Marine and Environmental Research, CIIMAR/CIMAR, Porto, Portugal. Electronic address: acampos@ciimar.up.pt.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Campos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004784:Environmental Monitoring / Q000379:methods*; D005880:Gills / Q000737:chemistry; D005982:Glutathione Transferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D049878:Mytilus / Q000235:genetics* / Q000378:metabolism; D011174:Portugal; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D013030:Spain; D014877:Water Pollution, Chemical / Q000032:analysis; D060753:Water Quality
chemical_list: D020033:Protein Isoforms; D005982:Glutathione Transferase
keywords: Affinity purification; Glutathione transferase; Mytilus galloprovincialis; Proteomics