Recombinant Human KDM3B protein

KDM3B (Lysine Demethylase 3B), also known as JMJD1B or TSGA, is a member of the Jumonji C (JmjC) domain-containing family of histone demethylases. It specifically catalyzes the removal of methyl groups from histone H3 lysine 9 (H3K9me1/me2), a post-translational modification associated with transcriptional regulation. Discovered as a key epigenetic regulator, KDM3B plays diverse roles in cellular processes, including gene expression, DNA repair, metabolic homeostasis, and cell differentiation. Its enzymatic activity relies on Fe²⁺ and α-ketoglutarate as cofactors, characteristic of the JmjC-dependent demethylase family.

Structurally, KDM3B contains conserved functional domains: the JmjC domain for catalytic activity, a zinc finger motif for substrate recognition, and nuclear localization signals. Its substrate specificity for H3K9 methylation links it to both gene activation (by erasing repressive marks) and heterochromatin modulation. Dysregulation of KDM3B has been implicated in cancer, where it exhibits context-dependent oncogenic or tumor-suppressive roles. For instance, it promotes tumor growth in certain cancers (e.g., colorectal, breast) by activating hypoxia-responsive or androgen receptor pathways, while acting as a suppressor in others (e.g., leukemia).

Recombinant KDM3B protein is typically produced using bacterial or mammalian expression systems, often fused with tags (e.g., His, GST) for purification and detection. It serves as a vital tool for in vitro studies, such as enzymatic assays, inhibitor screening, and chromatin interaction analyses. Recent research highlights its potential as a therapeutic target, particularly in cancers driven by epigenetic abnormalities. However, its dual roles in different biological contexts and the complexity of its interactions with co-regulators (e.g., HIF-1α, β-catenin) remain active areas of investigation. Understanding KDM3B's precise mechanisms and tissue-specific functions could advance epigenetic therapy development.