UniProt functional annotation for Q9H7B4



	UniProt functional annotation for Q9H7B4

UniProt code: Q9H7B4.

Organism: Homo sapiens (Human).

Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.

Function: Histone methyltransferase. Specifically methylates 'Lys-4' of histone H3, inducing di- and tri-methylation, but not monomethylation (PubMed:15235609, PubMed:22419068). Also methylates 'Lys-5' of histone H4 (PubMed:22419068). Plays an important role in transcriptional activation as a member of an RNA polymerase complex (PubMed:15235609). Binds DNA containing 5'-CCCTCC-3' or 5'-GAGGGG-3' sequences (PubMed:15235609). {ECO:0000269|PubMed:15235609, ECO:0000269|PubMed:22419068}.

Catalytic activity: Reaction=L-lysyl(4)-[histone H3] + 3 S-adenosyl-L-methionine = 3 H(+) + N(6),N(6),N(6)-trimethyl-L-lysyl(4)-[histone H3] + 3 S-adenosyl-L- homocysteine; Xref=Rhea:RHEA:60260, Rhea:RHEA-COMP:15537, Rhea:RHEA- COMP:15547, ChEBI:CHEBI:15378, ChEBI:CHEBI:29969, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789, ChEBI:CHEBI:61961; EC=2.1.1.354; Evidence={ECO:0000255|PROSITE-ProRule:PRU00907, ECO:0000269|PubMed:15235609, ECO:0000269|PubMed:22419068};

Activity regulation: Histone methyltransferase activity strongly stimulated by HSPCA. {ECO:0000269|PubMed:15235609}.

Subunit: Interacts with HSPCA (PubMed:15235609). Interacts with HELZ (PubMed:15235609). Interacts with POLR2A; the interaction may be indirect and may be mediated by HELZ (PubMed:15235609). Interacts with HSP90AA1; this interaction enhances SMYD3 histone-lysine N- methyltransferase (PubMed:25738358). {ECO:0000269|PubMed:15235609, ECO:0000269|PubMed:25738358}.

Subcellular location: Cytoplasm {ECO:0000269|PubMed:15235609}. Nucleus {ECO:0000269|PubMed:15235609, ECO:0000269|PubMed:25738358}. Note=Mainly cytoplasmic when cells are arrested at G0/G1. Accumulates in the nucleus at S phase and G2/M. {ECO:0000269|PubMed:15235609}.

Tissue specificity: Expressed in skeletal muscles and testis. Overexpressed in a majority of colorectal and hepatocellular carcinomas. {ECO:0000269|PubMed:15235609}.

Similarity: Belongs to the class V-like SAM-binding methyltransferase superfamily. Histone-lysine methyltransferase family. {ECO:0000255|PROSITE-ProRule:PRU00907}.

Annotations taken from UniProtKB at the EBI.


Organism:		Homo sapiens (Human).
Taxonomy:		Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.



Function:		Histone methyltransferase. Specifically methylates 'Lys-4' of histone H3, inducing di- and tri-methylation, but not monomethylation (PubMed:15235609, PubMed:22419068). Also methylates 'Lys-5' of histone H4 (PubMed:22419068). Plays an important role in transcriptional activation as a member of an RNA polymerase complex (PubMed:15235609). Binds DNA containing 5'-CCCTCC-3' or 5'-GAGGGG-3' sequences (PubMed:15235609). {ECO:0000269\|PubMed:15235609, ECO:0000269\|PubMed:22419068}.


Catalytic activity:		Reaction=L-lysyl(4)-[histone H3] + 3 S-adenosyl-L-methionine = 3 H(+) + N(6),N(6),N(6)-trimethyl-L-lysyl(4)-[histone H3] + 3 S-adenosyl-L- homocysteine; Xref=Rhea:RHEA:60260, Rhea:RHEA-COMP:15537, Rhea:RHEA- COMP:15547, ChEBI:CHEBI:15378, ChEBI:CHEBI:29969, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789, ChEBI:CHEBI:61961; EC=2.1.1.354; Evidence={ECO:0000255\|PROSITE-ProRule:PRU00907, ECO:0000269\|PubMed:15235609, ECO:0000269\|PubMed:22419068};
Activity regulation:		Histone methyltransferase activity strongly stimulated by HSPCA. {ECO:0000269\|PubMed:15235609}.
Subunit:		Interacts with HSPCA (PubMed:15235609). Interacts with HELZ (PubMed:15235609). Interacts with POLR2A; the interaction may be indirect and may be mediated by HELZ (PubMed:15235609). Interacts with HSP90AA1; this interaction enhances SMYD3 histone-lysine N- methyltransferase (PubMed:25738358). {ECO:0000269\|PubMed:15235609, ECO:0000269\|PubMed:25738358}.
Subcellular location:		Cytoplasm {ECO:0000269\|PubMed:15235609}. Nucleus {ECO:0000269\|PubMed:15235609, ECO:0000269\|PubMed:25738358}. Note=Mainly cytoplasmic when cells are arrested at G0/G1. Accumulates in the nucleus at S phase and G2/M. {ECO:0000269\|PubMed:15235609}.
Tissue specificity:		Expressed in skeletal muscles and testis. Overexpressed in a majority of colorectal and hepatocellular carcinomas. {ECO:0000269\|PubMed:15235609}.
Similarity:		Belongs to the class V-like SAM-binding methyltransferase superfamily. Histone-lysine methyltransferase family. {ECO:0000255\|PROSITE-ProRule:PRU00907}.