Microtubule-associated protein 1B light chain (MAP1B-LC1) negatively regulates the activity of tumor suppressor p53 in neuroblastoma cells.

The tumor suppressor and transcription factor p53 is a key modulator of cellular stress responses and can trigger apoptosis in many cell types, including neurons. In this study, we have shown that the Microtubule-Associated Protein 1B (MAP1B) light chain can interact with the tumor suppressor p53. We also demonstrate that both p53 and the MAP1B light chain (MAP1B-LC1) alter their localization from the cytoplasm to the nucleus when neuroblastoma cells, SH-SY5Y, are treated with doxorubicin. Additionally, we demonstrate that the MAP1B-LC1 negatively regulates p53-dependent transcriptional activity of a reporter construct driven by the p21 promoter. Consequently, MAP1B-LC1 binds to p53 and this interaction leads to the inhibition of doxorubicin-induced apoptosis in SH-SY5Y cells.