Solubilization methods and reference 2-DE map of cow milk fat globules.
Milk fat globules (MFGs) are secretory vesicles assembled and secreted by mammary epithelial cells during lactation. They consist of fat globules surrounded by a lipid bilayer membrane which is derived from the apical membrane of the lactating cells. MFGs contain, besides lipids, proteins from the apical plasma membrane and from the cytoplasmatic material. Their peculiar vesicle nature makes them a suitable and easily available source of biological material in monitoring the physiopathological state of the mammary gland. Unfortunately, the conspicuous lipidic component of MFGs consistently limits protein extraction and purification for MFG proteomic investigations. This work deals with the development of a suitable procedure for protein extraction from the cow MFGs in order to qualitatively and quantitatively improve 2-D electropherograms of the MFG. MFGs were purified from raw milk by centrifugation and then delipidated/precipitated. The resulting protein pellets were solubilised using four different 2-D SDS PAGE compatible lysis buffers. Applied methodological procedures for protein extraction and evaluation of the resulting 2-D protein-pattern are presented and discussed. Using these procedures a reference 2-D map of cow milk fat globules is also reported. The majority of the obtained identifications was represented by proteins involved in lipid synthesis or in fat globule secretion.
Bianchi
Laura
L
Functional Proteomics Laboratory, Department of Molecular Biology, Siena University, Siena, Italy.
Puglia
Michele
M
Landi
Claudia
C
Matteoni
Silvia
S
Perini
Daniele
D
Armini
Alessandro
A
Verani
Margherita
M
Trombetta
Claudia
C
Soldani
Patrizia
P
Roncada
Paola
P
Greppi
Gianfranco
G
Pallini
Vitaliano
V
Bini
Luca
L
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D006017:Glycolipids / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry*; D066292:Lipid Droplets; D008055:Lipids / Q000737:chemistry; D008892:Milk / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry; D020543:Proteome; D040901:Proteomics / Q000379:methods*; D016622:Silver Staining / Q000379:methods
D003902:Detergents; D006017:Glycolipids; D006023:Glycoproteins; D008055:Lipids; D011506:Proteins; D020543:Proteome; C110367:milk fat globule