TOB2 (transducer of ERBB2, 2) is an anti-proliferative protein that functions as a key regulator of cell cycle progression and mRNA metabolism. TOB2 inhibits cell cycle progression from G0/G1 to S phases through multiple mechanisms 1. The protein contains a conserved N-terminal BTG domain that serves as a protein-protein interaction module, enabling binding to transcription factors and deadenylase subunits CNOT7 and CNOT8 of the Ccr4-Not complex 1. TOB2 promotes global mRNA deadenylation and turnover by simultaneously interacting with poly(A)-binding protein (PABP) and Caf1 deadenylase, recruiting the deadenylase machinery to mRNA poly(A) tails 2. This process is regulated by phosphorylation, particularly at serine 254, which enhances PABP binding and accelerates mRNA decay of cell cycle-related transcripts 2. Beyond cell cycle control, TOB2 functions as a negative regulator of TLR-induced inflammatory responses by interacting with TRAF6 and MyD88, suppressing NF-κB and MAPK activation 3. In cancer contexts, TOB2 acts as a tumor suppressor, with decreased expression promoting proliferation and metastasis in renal cell carcinoma 45. TOB2 is ubiquitously expressed across tissues and plays important roles in development, spermatogenesis, and cellular homeostasis 67.