MLL2/KMT2B (D6X2E) Rabbit mAb (Carboxy-terminal Antigen) #63735

The Set1 histone methyltransferase protein was first identified in yeast as part of the Set1/COMPASS histone methyltransferase complex, which methylates histone H3 at Lys4 and functions as a transcriptional co-activator (1). While yeast contain only one known Set1 protein, mammals contain six Set1-related proteins: SET1A, SET1B, MLL1, MLL2, MLL3, and MLL4, all of which assemble into COMPASS-like complexes and methylate histone H3 at Lys4 (2,3). These Set1-related proteins are each found in distinct protein complexes, all of which share the common subunits WDR5, RBBP5, ASH2L, CXXC1, and DPY30, which are required for proper complex assembly and modulation of histone methyltransferase activity (2-6). MLL1 and MLL2 complexes contain the additional protein subunit, menin (6).MLL2, also known as histone-lysine N-methyltransferase 2B (KMT2B), functions to activate gene expression by mediating tri-methylation of histone H3 lysine 4 at the promoters of genes involved in embryogenesis and hematopoiesis, and is required for histone H3 lysine 4 tri-methylation at bivalent promoters in embryonic stem cells (7). Like MLL1, MLL2 is a large protein made up of approximately 2,700 amino acids that is cleaved by the Taspase 1 threonine endopeptidase to form N-terminal (MLL2-N) and C-terminal (MLL2-C) fragments, both of which are subunits of the functional MLL2/COMPASS complex. MLL2-N, MLL2-C, WDR5, RBBP5, and ASH2L define the core catalytic component of the MLL2/COMPASS complex, which is recruited to target genes to regulate transcription. MLL1 gene translocations are often associated with various hematological malignancies and thought to be a driving component of these types of leukemia. MLL2 is required for memory formation, proper glucose homeostasis, and cardiac lineage differentiation of mouse embryonic stem cells (8-11). A recent study has shown that MLL2 is required for survival of MLL-AF9-transformed cells, implicating MLL2 as a potential modulator of MLL1-rearranged leukemias (12). Mutations in MLL2 cause complex early-onset dystonia, and overexpression of MLL2 is associated with gastrointestinal diffuse large B-cell lymphoma (13,14).