RYBP (Ring1 and YY1 Binding Protein) is a multifunctional regulatory protein involved in epigenetic modulation, transcriptional regulation, and cellular processes such as apoptosis and differentiation. It was initially identified as a binding partner of Ring1 (a core component of Polycomb Repressive Complex 1. PRC1) and YY1 (Yin Yang 1), a transcription factor. RYBP plays a critical role in PRC1-mediated gene silencing by stabilizing the complex and enhancing its ubiquitination activity on histone H2A, a key epigenetic mark (H2AK119ub) associated with transcriptional repression. Beyond Polycomb-related functions, RYBP interacts with other proteins, including those involved in DNA damage response and apoptosis, such as Caspase-8 and p53. Studies highlight its dual role in cancer, acting as either a tumor suppressor or promoter depending on cellular context. For instance, RYBP loss is linked to tumor progression in certain cancers, while overexpression may induce apoptosis in others. Antibodies targeting RYBP are essential tools for studying its expression patterns, molecular interactions (e.g., via co-immunoprecipitation), and chromatin localization (e.g., ChIP-seq). They are widely used in cancer research, developmental biology, and investigations into epigenetic mechanisms. Commercial RYBP antibodies are typically validated for applications like Western blotting, immunohistochemistry, and immunofluorescence.