AKT1 and pulmonary fibrosis: Nevertheless, the ubiquitination of AKT can be reversed by CYLD, which is a deubiquitinating enzyme and plays a tumor suppressor role in inhibiting AKT activity by removing AKT K63-linked ubiquitin chains and serves as a negative regulator for AKT-mediated tumorigenesis or lung fibrosis [131] (Fig. 2).