Retinoblastoma-binding protein 6 (RBBP6)

Retinoblastoma-binding protein 6 (RBBP6) is a multifunctional 250-kDa protein that plays a critical role in cell cycle regulation, apoptosis, and mRNA processing. It is characterized by several conserved domains, including a RING finger domain that confers E3 ubiquitin ligase activity, allowing it to target proteins like p53, YB-1, and ZBTB38 for proteasomal degradation. RBBP6 acts as a negative regulator of the tumor suppressors p53 and pRb, often by enhancing the activity of MDM2 or through direct interaction, thereby promoting cell proliferation and survival in various malignancies. Overexpression of RBBP6 is frequently observed in cancers such as colorectal, lung, and breast cancer, where it is associated with poor prognosis and resistance to chemotherapy and radiotherapy. Consequently, RBBP6 is considered a promising therapeutic target; its inhibition has been shown to stabilize p53, induce apoptosis, and sensitize cancer cells to treatments like cisplatin and radiation. While no specific RBBP6 inhibitors are currently in clinical use, research into small molecules like ezetimibe and plerixafor, as well as antisense oligonucleotides, is ongoing to exploit its role in oncogenic pathways.

Other names

PACTP2P-RRBQ-1SNAMAMY038Proliferation potential-related proteinp53-associated cellular protein of testisRetinoblastoma-binding Q protein 1E3 ubiquitin-protein ligase RBBP6

RBBP6 acts as an E3 ubiquitin ligase or scaffold protein that promotes the degradation of tumor suppressors p53 and pRb, often by enhancing MDM2-mediated ubiquitination. Inhibition of RBBP6 stabilizes these tumor suppressors, leading to cell cycle arrest and apoptosis in cancer cells.