High impact information on MFGE8

• GLYCAM1, a member of the glycoprotein mucin family, is a component of the milk fat globule membrane (MFGM) [1].
• Since SBA binds N-acetylgalactosamine terminated oligosaccharides, the results indicated that N-acetylgalactosaminylation of bovine MFGM glycoproteins is stimulated during the lactation [2].
• Differential scanning calorimetry of bovine milk fat globule membranes (MFGM) yields five to eight transitions, depending on the conditions employed during isolation and assay of the membranes [3].
• In this report we present evidence that the E1, E2, and F endotherms derive from the major MFGM protein, xanthine oxidase [3].
• The integral and peripheral components of guinea-pig MFGM were identified by treating membrane preparations with sodium carbonate solutions at high pH and by partitioning the membrane proteins in solutions of Triton X-114 [4].

Biological context of MFGE8

• The observed similarity between several of the proteins of guinea-pig and bovine MFGM implies that these proteins may have specific functions related to milk secretion in mammary tissue, e.g. in the budding of milk-fat globules or the exocytosis of milk protein and lactose at the apical surface [4].
• The proteins associated with cell signalling or membrane/protein trafficking may provide insights into MFGM secretion mechanisms [5].
• Thus, the bulk of the proteins identified are new for bovine MFGM proteomics [5].
• Since expression of the disaccharide structure is influenced by peptide sequences near the glycosylation sites [Smith and Baenziger (1992) Proc. Natl. Acad. Sci. USA 89, 329-333], the site-specificity of the N-acetylgalactosaminylated sugar chains was investigated using bovine butyrophilin, a major MFGM glycoprotein with known primary structure [6].

Anatomical context of MFGE8

• Peptides prepared from immunoblots of Component 16 and GP 55, were shown by sequencing, to be similar to mouse MFG-E8 and a human milk protein of M(r) 46,000 [7].
• During lactation the mammary gland synthesizes a large amount of glycoproteins including those composing milk fat globule membrane (MFGM) [8].

Associations of MFGE8 with chemical compounds

• The primary milk fat globule membrane (MFGM) around freshly secreted milk fat globules consists of a unit membrane separated from the triglyceride core by a dense material [9].
• Thus, under normal farming conditions the alpha-tocopherol content will be highest in MFGM [10].
• There was no appreciable difference between the five brands of nonionic detergents used as regards the extractability of protein and the enzymatic activity of the extracted marker enzymes of MFGM, except that the solubilizing ability of Tween 20 was relatively low [11].
• The separation of MFGM from the skim milk proteins present in commercial buttermilk was carried out by the addition of sodium citrate followed by microfiltration through a membrane of 0.1-microm nominal pore size [12].
• Milk fat globule membranes (MFGM) were isolated from milk from cows injected intraperitoneally with dl-alpha-tocopherol acetate [10].

Analytical, diagnostic and therapeutic context of MFGE8

• Western blot analyses using several lectins revealed that reactivity of MFGM glycoproteins, especially 47K and 80K bands, to soybean agglutinin (SBA) remarkably increased during the lactation, while no change was observed for Ricinus communis agglutinin-I (RCA-I) binding [2].
• Comparison of guinea-pig xanthine oxidase and butyrophilin with proteins from bovine MFGM by peptide mapping procedures, showed that the two proteins in both species were similar, but not identical [4].
• Membrane filtration of commercial buttermilk was carried out to obtain isolates rich in MFGM material [12].
• However, no WFA binding was observed for protein bands after treatment of MFGM glycoproteins with N-glycanase [13].

References