title: Proteomic analysis of low-abundant integral plasma membrane proteins based on gels.
abstract: To characterize low-copy integral membrane proteins and offer some methods for human liver proteome projects, we fractionated highly purified rat liver plasma membrane (PM). PM was purified through two sucrose density gradient centrifugations, and treated with 0.1 M Na(2)CO(3), chloroform/methanol and Triton X-100. Proteins were separated by electrophoresis and submitted to mass spectrometry analysis. Four hundred and fifty-seven non-redundant membrane proteins were identified, of which 23% (105) were integral membrane proteins with one or more transmembrane domains. One hundred and fifty-three (33.5%) had no location annotation and 68 were unknown-function proteins. The proteins from different fractions were complementory. A database search for all identified proteins revealed that 53 proteins were involved in the cell communication pathway. More interestingly, more than 50% of the proteins had a protein abundance index concentration of less than 0.1 mol/l, and 12% proteins a concentration 100 times less than that of arginase 1 and actin.
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of National Education Committee, College of Life Science, Hunan Normal University, Changsha, PR China.
authors.forename: L-J
authors.initials: LJ
authors.lastname: Zhang
authors.forename: X-E
authors.initials: XE
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Peng
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Wei
authors.forename: R
authors.initials: R
authors.lastname: Cao
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.forename: J-X
authors.initials: JX
authors.lastname: Xiong
authors.forename: X-F
authors.initials: XF
authors.lastname: Yin
authors.forename: C
authors.initials: C
authors.lastname: Ping
authors.forename: S
authors.initials: S
authors.lastname: Liang
mesh_terms: D000818:Animals; D021941:Caveolae / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D005260:Female; D008099:Liver / Q000378:metabolism; D008297:Male; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D020543:Proteome / Q000737:chemistry*; D040901:Proteomics; D051381:Rats; D017207:Rats, Sprague-Dawley; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D008565:Membrane Proteins; D020543:Proteome