Human Prestin: A Candidate PE1 Protein Lacking Stringent Mass Spectrometric Evidence?

J Proteome Res. 2017 Dec 1;16(12):4531-4535. doi: 10.1021/acs.jproteome.7b00354. Epub 2017 Sep 21.


The evidence that any protein exists in the Human Proteome Project (HPP; protein evidence 1 or PE1) has revolved primarily (although not exclusively) around mass spectrometry (MS) (93% of PE1 proteins have MS evidence in the latest neXtProt release), with robust and stringent, well-curated metrics that have served the community well. This has led to a significant number of proteins still considered "missing" (i.e., PE2-4). Many PE2-4 proteins have MS evidence of unacceptable quality (small or not enough unitypic peptides and unacceptably high protein/peptide FDRs), transcriptomic, or antibody evidence. Here we use a Chromosome 7 PE2 example called Prestin to demonstrate that clear and robust criteria/metrics need to be developed for proteins that may not or cannot produce clear-cut MS evidence while possessing significant non-MS evidence, including disease-association data. Many of the PE2-4 proteins are inaccessible, spatiotemporally expressed in a limited way, or expressed at such a very low copy number as to be unable to be detected by current MS methodologies. We propose that the HPP community consider and lead a communal initiative to accelerate the discovery and characterization of these types of "missing" proteins.

Publication types

  • Letter

MeSH terms

  • Anion Transport Proteins / analysis*
  • Humans
  • Mass Spectrometry*
  • Proteome / analysis
  • Proteome / standards
  • Sulfate Transporters


  • Anion Transport Proteins
  • Proteome
  • SLC26A5 protein, human
  • Sulfate Transporters