title: Developmental changes in the milk fat globule membrane proteome during the transition from colostrum to milk.
abstract: Shotgun proteomics, using amine-reactive isobaric tags (iTRAQ), was used to quantify protein changes in milk fat globule membranes (MFGM) that were isolated from d 1 colostrum and compared with MFGM from d 7 milk. Eight Holstein cows were randomly assigned to 2 groups of 4 cow sample pools for a simple replication of this proteomic analysis using iTRAQ. The iTRAQ labeled peptides from the experiment sample pools were fractionated by strong cation exchange chromatography followed by further fractionation on a microcapillary high performance liquid chromatograph connected to a nanospray-tandem mass spectrometer. Data analysis identified 138 bovine proteins in the MFGM with 26 proteins upregulated and 19 proteins downregulated in d 7 MFGM compared with colostrum MFGM. Mucin 1 and 15 were upregulated greater than 7-fold in MFGM from d 7 milk compared with colostrum MFGM. The tripartite complex of proteins of adipophilin, butyrophilin, and xanthine dehydrogenase were individually upregulated in d 7 MFGM 3.4-, 3.2-, and 2.6-fold, respectively, compared with colostrum MFGM. Additional proteins associated with various aspects of lipid transport synthesis and secretion such as acyl-CoA synthetase, lanosterol synthase, lysophosphatidic acid acyltransferase, and fatty acid binding protein were upregulated 2.6- to 5.1-fold in d 7 MFGM compared with colostrum MFGM. In contrast, apolipoproteins A1, C-III, E, and A-IV were downregulated 2.6- to 4.3-fold in d 7 MFGM compared with colostrum MFGM. These data demonstrate that quantitative shotgun proteomics has great potential to provide new insights into mammary development.
authors.affiliation: Periparturient Diseases of Cattle Research Unit, USDA, Agricultural Research Service, National Animal Disease Center, Ames, IA 50010, USA. tim.reinhardt@ars.usda.gov
authors.forename: T A
authors.initials: TA
authors.lastname: Reinhardt
authors.forename: J D
authors.initials: JD
authors.lastname: Lippolis
mesh_terms: D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000662:veterinary; D003126:Colostrum / Q000737:chemistry*; D005260:Female; D005786:Gene Expression Regulation; D006017:Glycolipids / Q000032:analysis / Q000737:chemistry*; D006023:Glycoproteins / Q000032:analysis / Q000737:chemistry*; D066292:Lipid Droplets; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry*; D008892:Milk / Q000737:chemistry*; D040901:Proteomics; D011897:Random Allocation; D053719:Tandem Mass Spectrometry / Q000379:methods / Q000662:veterinary
chemical_list: D006017:Glycolipids; D006023:Glycoproteins; D008565:Membrane Proteins; C110367:milk fat globule