UniProt functional annotation for Q7L2J0



	UniProt functional annotation for Q7L2J0

UniProt code: Q7L2J0.

Organism: Homo sapiens (Human).

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

Function: S-adenosyl-L-methionine-dependent methyltransferase that adds a methylphosphate cap at the 5'-end of 7SK snRNA (7SK RNA), leading to stabilize it (PubMed:17643375, PubMed:19906723, PubMed:30559425). Also has a non-enzymatic function as part of the 7SK RNP complex: the 7SK RNP complex sequesters the positive transcription elongation factor b (P-TEFb) in a large inactive 7SK RNP complex preventing RNA polymerase II phosphorylation and subsequent transcriptional elongation (PubMed:17643375). The 7SK RNP complex also promotes snRNA gene transcription by RNA polymerase II via interaction with the little elongation complex (LEC) (PubMed:28254838). In the 7SK RNP complex, MEPCE is required to stabilize 7SK RNA and facilitate the assembly of 7SK RNP complex (PubMed:19906723). MEPCE has a non-enzymatic function in the 7SK RNP complex; interaction with LARP7 within the 7SK RNP complex occluding its catalytic center (PubMed:19906723). {ECO:0000269|PubMed:17643375, ECO:0000269|PubMed:19906723, ECO:0000269|PubMed:28254838, ECO:0000269|PubMed:30559425}.

Catalytic activity: Reaction=a 5'-triphospho-guanosine-ribonucleotide-snRNA + S-adenosyl-L- methionine = a 5'-methyltriphosphate-guanosine-ribonucleotide-snRNA + S-adenosyl-L-homocysteine; Xref=Rhea:RHEA:58780, Rhea:RHEA- COMP:15220, Rhea:RHEA-COMP:15221, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789, ChEBI:CHEBI:138278, ChEBI:CHEBI:142789; Evidence={ECO:0000269|PubMed:17643375, ECO:0000269|PubMed:19906723, ECO:0000269|PubMed:30559425}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:58781; Evidence={ECO:0000269|PubMed:17643375, ECO:0000269|PubMed:19906723, ECO:0000269|PubMed:30559425};

Subunit: Core component of the 7SK RNP complex, at least composed of 7SK RNA, LARP7, MEPCE, HEXIM1 (or HEXIM2) and P-TEFb (composed of CDK9 and CCNT1/cyclin-T1) (PubMed:17643375, PubMed:19906723). Interacts with METTL16 (PubMed:29051200). Interacts with RBM7; upon genotoxic stress this interaction is enhanced, triggering the release of inactive P-TEFb complex from the core, yielding to P-TEFb complex activation (PubMed:30824372). {ECO:0000269|PubMed:17643375, ECO:0000269|PubMed:19906723, ECO:0000269|PubMed:29051200, ECO:0000269|PubMed:30824372}.

Subcellular location: Nucleus {ECO:0000269|PubMed:19906723}.

Tissue specificity: Expressed in chronic myeloid leukemia cells, adrenal gland, brain, cerebellum, kidney, lung, mammary gland and testis (PubMed:12358911). Weakly or not expressed in other tissues (PubMed:12358911). {ECO:0000269|PubMed:12358911}.

Similarity: Belongs to the methyltransferase superfamily. {ECO:0000305}.

Sequence caution: Sequence=AAF74767.1; Type=Erroneous initiation; Evidence={ECO:0000305}; Sequence=AAH16396.1; Type=Erroneous initiation; Evidence={ECO:0000305}; Sequence=BAA91040.1; Type=Erroneous initiation; Evidence={ECO:0000305};

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:		S-adenosyl-L-methionine-dependent methyltransferase that adds a methylphosphate cap at the 5'-end of 7SK snRNA (7SK RNA), leading to stabilize it (PubMed:17643375, PubMed:19906723, PubMed:30559425). Also has a non-enzymatic function as part of the 7SK RNP complex: the 7SK RNP complex sequesters the positive transcription elongation factor b (P-TEFb) in a large inactive 7SK RNP complex preventing RNA polymerase II phosphorylation and subsequent transcriptional elongation (PubMed:17643375). The 7SK RNP complex also promotes snRNA gene transcription by RNA polymerase II via interaction with the little elongation complex (LEC) (PubMed:28254838). In the 7SK RNP complex, MEPCE is required to stabilize 7SK RNA and facilitate the assembly of 7SK RNP complex (PubMed:19906723). MEPCE has a non-enzymatic function in the 7SK RNP complex; interaction with LARP7 within the 7SK RNP complex occluding its catalytic center (PubMed:19906723). {ECO:0000269\|PubMed:17643375, ECO:0000269\|PubMed:19906723, ECO:0000269\|PubMed:28254838, ECO:0000269\|PubMed:30559425}.


Catalytic activity:		Reaction=a 5'-triphospho-guanosine-ribonucleotide-snRNA + S-adenosyl-L- methionine = a 5'-methyltriphosphate-guanosine-ribonucleotide-snRNA + S-adenosyl-L-homocysteine; Xref=Rhea:RHEA:58780, Rhea:RHEA- COMP:15220, Rhea:RHEA-COMP:15221, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789, ChEBI:CHEBI:138278, ChEBI:CHEBI:142789; Evidence={ECO:0000269\|PubMed:17643375, ECO:0000269\|PubMed:19906723, ECO:0000269\|PubMed:30559425}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:58781; Evidence={ECO:0000269\|PubMed:17643375, ECO:0000269\|PubMed:19906723, ECO:0000269\|PubMed:30559425};
Subunit:		Core component of the 7SK RNP complex, at least composed of 7SK RNA, LARP7, MEPCE, HEXIM1 (or HEXIM2) and P-TEFb (composed of CDK9 and CCNT1/cyclin-T1) (PubMed:17643375, PubMed:19906723). Interacts with METTL16 (PubMed:29051200). Interacts with RBM7; upon genotoxic stress this interaction is enhanced, triggering the release of inactive P-TEFb complex from the core, yielding to P-TEFb complex activation (PubMed:30824372). {ECO:0000269\|PubMed:17643375, ECO:0000269\|PubMed:19906723, ECO:0000269\|PubMed:29051200, ECO:0000269\|PubMed:30824372}.
Subcellular location:		Nucleus {ECO:0000269\|PubMed:19906723}.
Tissue specificity:		Expressed in chronic myeloid leukemia cells, adrenal gland, brain, cerebellum, kidney, lung, mammary gland and testis (PubMed:12358911). Weakly or not expressed in other tissues (PubMed:12358911). {ECO:0000269\|PubMed:12358911}.
Similarity:		Belongs to the methyltransferase superfamily. {ECO:0000305}.
Sequence caution:		Sequence=AAF74767.1; Type=Erroneous initiation; Evidence={ECO:0000305}; Sequence=AAH16396.1; Type=Erroneous initiation; Evidence={ECO:0000305}; Sequence=BAA91040.1; Type=Erroneous initiation; Evidence={ECO:0000305};