Predominant identification of RNA-binding proteins in Fas-induced apoptosis by proteome analysis

Proteome analysis of Jurkat T cells was performed in order to identify prot eins that are modified during apoptosis, Subtractive analysis of two-dimens ional gel patterns of apoptotic and nonapoptotic cells revealed differences in 45 protein spots. 37 protein spots of 21 different proteins were identi fied by peptide mass fingerprinting using matrix-assisted laser desorption/ ionization mass spectrometry, The hnRNPs A0, A2/B1, A3, K and R; the splici ng factors p54(nrb), SRp30c, ASF-2, and KH-type splicing regulatory protein (FUSE-binding protein 2); and alpha NAG, NS1-associated protein 1, and pol y(A)-binding protein 4 were hitherto unknown to be involved in apoptosis, T he putative cleavage sites of the majority of the proteins could be calcula ted by the molecular masses and isoelectric points in the two-dimensional e lectrophoresis gel, the peptide mass fingerprints, and after translation by treatment with recombinant caspase-3, Remarkably, 15 of the 21 identified proteins contained the RNP or KH motif, the best characterized RNA-binding motifs.