''Inactive ubiquitin carboxyl-terminal hydrolase 53'' is a protein that in humans is encoded by the ''USP53'' gene. Although USP53 is classified as a deubiquitinating enzyme based on sequence homology to other proteases from this group, it lacks a functionally essential histidine in the catalytic domaine and activity assays suggest that USP53 is catalytically inactive. Even though USP53 is devoid of catalytic activity, USP53 serves important physiological functions: mutations in ''Usp53'' have been shown to cause progressive hearing loss in mice, as well as late-onset hearing loss and cholestasis in humans. USP53 localizes at cellular tight junctions and interacts with

tight junction protein 2 Tight junction protein ZO-2 is a protein that in humans is encoded by the ''TJP2'' gene. Tight junction proteins (TJPs) belong to a family of membrane-associated guanylate kinase (MAGUK) homologs that are involved in the organization of epithelia ...

(TJP2). Mutations in ''TJP2'' have also been shown to cause hearing impairments and cholestasis.

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