Employing non-targeted interactomics approach and subcellular fractionation to increase our understanding of the ghost proteome

Diego Fernando Garcia-Del Rio; Tristan Cardon; Sven Eyckerman; Isabelle Fournier; Amelie Bonnefond; Kris Gevaert; Michel Salzet

doi:10.1016/j.isci.2023.105943

Employing non-targeted interactomics approach and subcellular fractionation to increase our understanding of the ghost proteome

iScience. 2023 Jan 6;26(2):105943. doi: 10.1016/j.isci.2023.105943. eCollection 2023 Feb 17.

Authors

Diego Fernando Garcia-Del Rio^{1

2

3}, Tristan Cardon¹, Sven Eyckerman^{2

3}, Isabelle Fournier¹, Amelie Bonnefond⁴, Kris Gevaert^{2

3}, Michel Salzet¹

Affiliations

¹ Université de Lille, University Lille, CHU Lille, Inserm U1192 - Protéomique Réponse Inflammatoire Spectrométrie de Masse - PRISM, 59000 Lille, France.
² VIB-UGent Center for Medical Biotechnology, VIB, 9052 Ghent, Belgium.
³ Department of Biomolecular Medicine, Ghent University, 9052 Ghent, Belgium.
⁴ Inserm/CNRS UMR 1283/8199, Pasteur Institute of Lille, EGID, Lille, France University of Lille, Lille, France.

Abstract

Eukaryotic mRNA has long been considered monocistronic, but nowadays, alternative proteins (AltProts) challenge this tenet. The alternative or ghost proteome has largely been neglected and the involvement of AltProts in biological processes. Here, we used subcellular fractionation to increase the information about AltProts and facilitate the detection of protein-protein interactions by the identification of crosslinked peptides. In total, 112 unique AltProts were identified, and we were able to identify 220 crosslinks without peptide enrichment. Among these, 16 crosslinks between AltProts and Referenced Proteins (RefProts) were identified. We further focused on specific examples such as the interaction between IP_2292176 (AltFAM227B) and HLA-B, in which this protein could be a potential new immunopeptide, and the interactions between HIST1H4F and several AltProts which can play a role in mRNA transcription. Thanks to the study of the interactome and the localization of AltProts, we can reveal more of the importance of the ghost proteome.

Keywords: Cell biology; Molecular network; Proteomics.