MOB2 (MOB kinase activator 2) is a regulatory protein that functions as a tumor suppressor through multiple signaling pathways. Primary Function: MOB2 serves as a coactivator that binds to and negatively regulates NDR serine-threonine kinases 1, though it can also positively regulate NDR kinases in specific contexts 2. The protein localizes to the cytosol, nucleoplasm, and nucleus, where it participates in signal transduction [GO annotations]. Mechanism: MOB2 interacts with NDR1 and NDR2 kinases, and this association can either stimulate or inhibit kinase activity depending on binding state and cellular context 21. Notably, MOB2 promotes cAMP/PKA signaling in a cAMP-dependent manner and negatively regulates the FAK/Akt pathway through integrin-dependent mechanisms 3. MOB2 also functions in mitotic chromosome 11 by scaffolding MST2 and Fry proteins that activate NDR1 4. Disease Relevance: MOB2 is significantly downregulated in glioblastoma and hepatocellular carcinoma 35. Restoration of MOB2 expression suppresses malignant phenotypes including migration, invasion, and clonogenic growth, while its depletion enhances metastasis 3. Clinical Significance: MOB2 overexpression induces apoptosis and G0/G1 cell cycle arrest in hepatic cancer cells 5, suggesting therapeutic potential through combined targeting of FAK and cAMP pathways 3.