Proteomics reveals how the tardigrade damage suppressor protein teaches transfected human cells to survive UV-C stress

Abstract

The genome sequencing of the tardigrade Ramazzottius varieornatus revealed a unique nucleosome-binding protein, named Damage Suppressor (Dsup), which resulted to be crucial for the extraordinary abilities of tardigrades in surviving extreme stresses, such as UV. Evidence in Dsup transfected human cells, suggests that Dsup mediates an overall response of DNA damage signaling, DNA repair and cell cycle regulation resulting in an acquired resistance to stress. Given these promising outcomes, our study attempts to provide a wider comprehension of the molecular mechanisms modulated by Dsup in human cells, and to explore the Dsup-activated molecular pathways under stress. We performed a differential proteomic analysis of Dsup-transfected and control human cells, under basal condition and at 24-hour recovery after exposure to UV-C. We demonstrate by enrichment and network analyses, for the first time, that even in the absence of external stimuli and more significantly after stress, Dsup activates mechanisms involved with the Unfolded Protein Response, the mRNA processing and stability, cytoplasmic stress granules, the DNA Damage Response and the telomere maintenance. In conclusion, our results shed new light on Dsup-mediated protective mechanisms, and increase our knowledge of the molecular machineries of extraordinary protection against UV-C stress.