first Tudor domain found in Jumonji domain-containing protein 2B (JMJD2B) and similar proteins
JMJD2B, also called lysine-specific demethylase 4B (KDM4B), or JmjC domain-containing histone demethylation protein 3B (JHDM3B), specifically antagonizes the tri-methyl group from H3K9 in pericentric heterochromatin and reduces H3K36 methylation in mammalian cells. It plays an essential role in the growth regulation of cancer cells by modulating the G1-S transition and promotes cell-cycle progression through the regulation of cyclin-dependent kinase 6 (CDK6). It interacts with heat shock protein 90 (Hsp90) and its stability can be regulated by Hsp90. JMJD2B also functions as a direct transcriptional target of p53, which induces its expression through promoter binding. Moreover, JMJD2B expression can be controlled by hypoxia-inducible factor 1alpha (HIF1alpha) in colorectal cancer and estrogen receptor alpha (ERalpha) in breast cancer. It is also involved in bladder, lung, and gastric cancer. JMJD2B contains jmjN and jmjC domains in the N-terminal region, followed by a canonical plant homeodomain (PHD) domain, a noncanonical extended PHD domain, and tandem Tudor domains. The model corresponds to the first Tudor domain. The Tudor domain binds to proteins with dimethylated arginine or lysine residues, and may also bind methylated histone tails to facilitate protein-protein interactions.