Deubiquitinating enzymes (DUBs) serve to maintain cellular homeostasis via
protein ubiquitination and exert diverse regulatory functions in
cancers and other diseases. Much progress has been made in characterizing
biological roles of DUBs over the decades, yet the specific functions of many subclass members remain largely unexplored. It was not until recent years that the role of
ubiquitin-specific-processing protease 35 (USP35) in
cancers began to be understood. Here, we focus on delineating the roles and underlying mechanisms of USP35 in
non-small cell lung cancer (NSCLC). The isobaric tags for relative and absolute quantitation (iTRAQ) comparative proteomic approach were employed to identify differentially expressed
proteins (DEPs) in H1299 cells induced by USP35 overexpression or silencing. Among the potential interactome of USP35, ribosome-
binding protein 1 (RRBP1), a membrane-bound
protein in endoplasmic reticulum (ER), captured our attentions. RRBP1 expression was found to positively correlate with USP35 levels in both genetically modified cells and human NSCLC tissues. Concordantly, both RRBP1 expression and USP35 expression were found to positively correlate with poor prognoses in
lung adenocarcinoma patients. At the molecular level, USP35 was verified to directly interact with RRBP1 to prevent it from proteasomal-dependent degradation. Functionally, USP35 alleviated ER stress-induced cell apoptosis by stabilizing RRBP1 in NSCLC cells. Collectively, these findings indicate that USP35 plays a critical role in resisting ER stress-induced cell death through deubiquitinating RRBP1, hence providing a rationale to target the USP35-RRBP1 axis as an alternative therapeutic option for NSCLC.