title: The identification and characterization of membranome components.
abstract: Analyses of proteins from a number of proteomic studies of cell membranes have demonstrated that a significant component of the identified proteins is not predicted to contain transmembrane regions. The presence of such proteins may arise as a result of contamination of the membrane preparations or through real associations. Our aim was to identify integral proteins as well as those that are intimately associated with the microsomal membranes of K562 cells. Isolated membranes were treated under conditions reported to remove noncovalently associated 'peripheral' proteins and the residual proteins were SDS-PAGE-separated and analyzed by LC-MS/MS. Tandem lectin affinity was also examined as a complementary approach for the enrichment of membrane glycoproteins. Approximately 41% of the isolated proteins were assigned as membrane proteins based on the presence of transmembrane regions or covalent post-translational modifications that could account for membrane association. Collectively, these results indicate that there is a significant component of non integral proteins that appear to be as closely associated with membranes as integral elements.
authors.affiliation: Manitoba Centre for Proteomics and Systems Biology, Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada.
authors.forename: Dhimankrishna
authors.initials: D
authors.lastname: Ghosh
authors.forename: Ron C
authors.initials: RC
authors.lastname: Beavis
authors.forename: John A
authors.initials: JA
authors.lastname: Wilkins
mesh_terms: D002458:Cell Fractionation / Q000379:methods; D002853:Chromatography, Liquid; D003208:Concanavalin A / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000032:analysis / Q000737:chemistry; D006801:Humans; D020014:K562 Cells; D008565:Membrane Proteins / Q000032:analysis*; D008861:Microsomes / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry; D014909:Wheat Germ Agglutinins / Q000737:chemistry
chemical_list: D006023:Glycoproteins; D008565:Membrane Proteins; D014909:Wheat Germ Agglutinins; D003208:Concanavalin A