Recombinant Human RBBP9 protein

RBBP9 (Retinoblastoma-binding protein 9) is a conserved eukaryotic protein implicated in cellular processes such as proliferation, apoptosis, and signal transduction. Initially identified as a retinoblastoma protein (Rb)-interacting partner, it shares homology with the RBBP family but exhibits distinct functional characteristics. Structurally, RBBP9 contains a serine hydrolase domain with catalytic triads typical of α/β-hydrolase enzymes, though its precise enzymatic activity remains debated. Studies suggest roles in modulating TGF-β/SMAD signaling and insulin receptor trafficking, linking it to cancer progression and metabolic regulation. Elevated RBBP9 expression correlates with poor prognosis in pancreatic, breast, and liver cancers, where it may promote tumorigenesis by enhancing cell survival and chemoresistance.

Recombinant RBBP9 protein is engineered for in vitro studies to dissect its molecular mechanisms. Typically produced in E. coli or mammalian expression systems, it undergoes purification via affinity chromatography (e.g., His-tag) followed by refolding or size-exclusion chromatography to ensure proper conformation. Functional validation includes assessing interactions with Rb or TGF-β pathway components through pull-down assays, and enzymatic activity screening using fluorogenic substrates. Researchers employ recombinant RBBP9 to study its structural dynamics via crystallography, map binding interfaces through mutagenesis, and develop inhibitory compounds for therapeutic exploration. Its role in chemotherapy resistance has spurred interest in targeting RBBP9 for combination therapies. Current research gaps involve clarifying its physiological substrates and resolving conflicting data about its hydrolase activity versus scaffolding functions in different cellular contexts.