Updated project metadata. E3 ubiquitin-ligases are important for the cellular protein homeostasis and their deregulation is implicated in cancer. The E3 ubiquitin-ligase Hakai is involved in tumour progression and metastasis, through the regulation of the tumour suppressor E-cadherin. Hakai is overexpressed in colon cancer, however, the implication in colitis-associated cancer is unknown. Here, we investigated the potential role of Hakai in intestinal inflammation and cancer bowel disease.Several mouse models of colitis and associated cancer were used including AOM-DSS, acute colitis, and genetically modified mice deficient for the IL-10 gene, to analyse Hakai expression by immunohistochemistry. Interactome analysis of Hakai was performed and effect on selected protein was determined by plasmid and siRNA transfection, western-blotting, immunoprecipitation, immunofluorescence and ubiquitination assays. Lipid accumulation was assayed by oil red staining. Immunohistochemistry was also performed in inflamed colon biopsies from ulcerative colitis, Crohn's disease and colorectal cancer patients. Our results show that Hakai was downregulated in inflammatory tissues in different mouse models. Fatty Acid Synthase (FASN) protein was identified as a novel Hakai-interacting protein. Hakai induces FASN ubiquitination and degradation via lysosome, thus regulating FASN-mediated lipid accumulation. An inverse expression of FASN with Hakai expression was detected in inflammatory AOM/DSS mouse model. In conclusion, Hakai regulates FASN ubiquitination and degradation, resulting in the regulation of FASN-mediated lipid accumulation, which is associated to the development of inflammatory bowel disease. The interaction between Hakai and FASN may be an important mechanism for the homeostasis of intestinal barrier function and in the pathogenesis of this disease.