Component of the Set1/Ash2 histone methyltransferase (HMT) complex, a complex that specifically methylates 'Lys-4' of histone H3, but not if the neighboring 'Lys-9' residue is already methylated. As part of the MLL1/MLL complex it is involved in methylation and dimethylation at 'Lys-4' of histone H3. May function as a transcriptional regulator. May play a role in hematopoiesis. Interacts with HCFC1. Core component of several methyltransferase-containing complexes including MLL1/MLL, ASCOM, MLL2/MLL3 and MLL3/MLL4. Each complex is at least composed of ASH2L, RBBP5, DPY30, WDR5, one or more specific histone methyltransferases (MLL, MLL2, MLL3 and MLL4), and the facultative components C16orf53/PA1, C17orf49, CHD8, E2F6, HCFC1, HCFC2, HSP70, INO80C, KDM6A, KANSL1, LAS1L, MAX, MCRS1, MEN1, MGA, KAT8/MOF, NCOA6, PAXIP1/PTIP, PELP1, PHF20, PRP31, RING2, RUVB1/TIP49A, RUVB2/TIP49B, SENP3, TAF1, TAF4, TAF6, TAF7, TAF9 and TEX10. Interacts with DPY30 and RBBP5; the interaction is direct. Component of the SET1 complex, at least composed of the catalytic subunit (SETD1A or SETD1B), WDR5, WDR82, RBBP5, ASH2L/ASH2, CXXC1/CFP1, HCFC1 and DPY30. Interacts with SETD1A and SETD1B. Ubiquitously expressed. Predominantly expressed in adult heart and testis and fetal lung and liver, with barely detectable expression in adult lung, liver, kidney, prostate, and peripheral leukocytes. 3 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Protein type: Methyltransferase; Transcription regulation
Molecular Function: protein binding; DNA binding; histone lysine N-methyltransferase activity (H3-K4 specific); metal ion binding
Biological Process: transcription from RNA polymerase II promoter; regulation of transcription, DNA-dependent; transcription, DNA-dependent; response to estrogen stimulus; histone H3-K4 methylation; positive regulation of cell proliferation; positive regulation of transcription from RNA polymerase II promoter; hemopoiesis; response to DNA damage stimulus
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.