A shot to missing protein from an aneuploidy cell line

With fast development of proteomic technology, the scale of missing proteins (MPs) has being continuously shrunk, approximately 1,470 MPs not explored yet. Discovery of MPs, on the other hand, is appearing more difficult. In some aneuploid cells, the abundance changes are proportional to the additional chromosome(s), while several MPs were found within them. Herein, we hypothesize that a stable aneuploid cell line with the increased chromosomes was a useful material that assists MP exploration. Ker-CT cell line with trisomy at chromosome 5 and 20 was selected. With a combination strategy of RNA-Seq and LC-M/MS, a total of 22,178 transcripts and 8,846 proteins were identified in Ker-CT. Although the transcripts corresponding to 31 and 32 MP genes located at chromosome 5 and 20 were detected, none of MPs was found in Ker-CT. Surprisingly, 3 MPs containing at least two unique non-nest peptides of length ≥9 amino acid were identified in Ker-CT, whose genes are located in chromosome 3 and 10. Furthermore, the 3 MPs were verified using the method of parallel reaction monitoring (PRM).