title: Proteomic analysis of mouse liver plasma membrane: use of differential extraction to enrich hydrophobic membrane proteins.
abstract: To comprehensively identify proteins of liver plasma membrane (PM), we isolated PMs from mouse liver by sucrose density gradient centrifugation. An optimized extraction method for whole PM proteins and several methods of differential extraction expected to enrich hydrophobic membrane proteins were tested. The extracted PM proteins were separated by 2-DE, and were identified by MALDI-TOF-MS, and ESI-quadrupole-TOF MS. As the complementary method, 1-DE-MS/MS was also used to identify PM proteins. The optimized lysis buffer containing urea, thiourea, CHAPS and NP-40 was able to extract more PM proteins, and treatment of PM samples with chloroform/methanol and sodium carbonate led to enrichment of more hydrophobic PM proteins. From the mouse liver PM fraction, 175 non-redundant gene products were identified, of which 88 (about 50%) were integral membrane proteins with one to seven transmembrane domains. The remaining products were probably membrane-associated and cytosolic proteins. The function distribution of all the identified liver PM proteins was analyzed; 40% represented enzymes, 12% receptors and 9% proteins with unknown function.
authors.affiliation: College of Life Science, Hunan Normal University, Changsha, PR China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Zhang
authors.forename: Jinyun
authors.initials: J
authors.lastname: Xie
authors.forename: Xi'e
authors.initials: X
authors.lastname: Wang
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Liu
authors.forename: Xinke
authors.initials: X
authors.lastname: Tang
authors.forename: Rui
authors.initials: R
authors.lastname: Cao
authors.forename: Weijun
authors.initials: W
authors.lastname: Hu
authors.forename: Song
authors.initials: S
authors.lastname: Nie
authors.forename: Chunming
authors.initials: C
authors.lastname: Fan
authors.forename: Songping
authors.initials: S
authors.lastname: Liang
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry* / Q000648:ultrastructure; D002499:Centrifugation, Density Gradient / Q000379:methods; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D004798:Enzymes / Q000737:chemistry / Q000302:isolation & purification; D007202:Indicators and Reagents; D008099:Liver / Q000737:chemistry* / Q000502:physiology; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D051379:Mice; D008854:Microscopy, Electron / Q000379:methods; D008970:Molecular Weight; D040901:Proteomics / Q000379:methods; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004798:Enzymes; D007202:Indicators and Reagents; D008565:Membrane Proteins