Proteomic analysis of the differential protein expression reveals nuclear GAPDH in activated T lymphocytes.
Despite the important role of T cell activation in the adaptive immunity, very little is known about the functions of proteins that are differentially expressed in the activated T cells. In this study, we have employed proteomic approach to study the differentially expressed proteins in activated T cells. A total of 25 proteins was characterized that displayed a decreased expression, while a total of 20 proteins was characterized that displayed an increased expression in the activated T cells. Among them, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was identified unexpectedly as one of the up-regulated proteins. Western blot analysis of proteins separated by 2-dimensional gel electrophoresis had identified several modified GAPDHs which were detectable only in the activated T cells, but not in resting T cells. These modified GAPDHs had higher molecular mass and more basic PI, and were present in the nucleus of activated T cells. Promoter occupancy studies by chromatin immunoprecipitation assay revealed that nuclear GAPDH could be detected in the promoter of genes that were up-regulated during T cell activation, but not in the promoter of genes that were not unaffected or down-regulated. Our results suggest that nuclear GAPDH may function as transcriptional regulator in activated T cells.
Sheng
Wei-Yun
WY
Department of Molecular and Cellular Biology, Chang Gung University, Kwei-San, Taiwan.
Wang
Tzu-Chien V
TC
D001483:Base Sequence; D015153:Blotting, Western; D002467:Cell Nucleus / Q000201:enzymology; D047369:Chromatin Immunoprecipitation; D017931:DNA Primers; D015180:Electrophoresis, Gel, Two-Dimensional; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D008213:Lymphocyte Activation; D018613:Microscopy, Confocal; D040901:Proteomics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000201:enzymology*; D014158:Transcription, Genetic
D017931:DNA Primers; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases