Updated project metadata. A role for immunoproteasome in the regulation of intestinal permeability has been previously suggested both in mice during water avoidance stress (WAS) and in patients with irritable bowel syndrome (IBS). We thus aimed (i) to evaluate the colonic proteome in wild-type (wt) and β2i immunoproteasome subunit knock-out (β2i-/-) mice during WAS and (ii) to investigate the colonic expression of 49 ubiquitinated-proteins in diarrhea-predominant IBS patients (IBS-D).