Subcellular proteomics of cell differentiation: quantitative analysis of the plasma membrane proteome of Caco-2 cells.
Human colorectal carcinoma (Caco-2) cells undergo in culture spontaneous enterocytic differentiation, characterized by polarization and appearance of the functional apical brush border membrane. To provide insights into the biology of differentiation, we have performed a comparative proteomic analysis of the plasma membranes from proliferating cells (PCs) and the apical membranes from differentiated cells (DCs). Proteins were resolved by SDS-PAGE, in-gel digested and analyzed by RP-LC and MS/MS. Alternatively, proteins were digested in solution, and tryptic peptides were labeled with isotopic tags and analyzed by 2-D LC followed by MS/MS. Among the 1125 proteins identified in both proteomes, 76 were found to be significantly increased in the membranes of DCs and 61 were increased in PCs. Majority of the proteins increased in the apical membranes were metabolic enzymes, proteins involved in the maintenance of cellular structure, transmembrane transporters, and proteins regulating vesicular transport. In contrast, majority of the proteins increased in the membranes of PCs were involved in gene expression, protein synthesis, and folding. Both groups contained many novel proteins with yet to be identified functions, which could provide potential new markers of the intestinal cells or of colorectal cancer.
Pshezhetsky
Alexey V
AV
Sainte-Justine Hospital Research Center, University of Montreal, Montreal, Quebec, Canada. alexei.pchejetski@umontreal.ca
Fedjaev
Michael
M
Ashmarina
Lyudmila
L
Mazur
Alexander
A
Budman
Lorne
L
Sinnett
Daniel
D
Labuda
Damian
D
Beaulieu
Jean-François
JF
Ménard
Daniel
D
Nifant'ev
Ilya
I
Levy
Emile
E
D017302:Annexins / Q000378:metabolism; D018938:Caco-2 Cells; D002454:Cell Differentiation; D002458:Cell Fractionation; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D049109:Cell Proliferation; D002853:Chromatography, Liquid; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004798:Enzymes / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D020543:Proteome / Q000032:analysis / Q000378:metabolism*; D053719:Tandem Mass Spectrometry; D033921:Vesicular Transport Proteins / Q000378:metabolism
D017302:Annexins; D003598:Cytoskeletal Proteins; D004798:Enzymes; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D020543:Proteome; D033921:Vesicular Transport Proteins