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MGP003667

UniProt Annotations

Entry Information
Gene NameRNA guanylyltransferase and 5'-phosphatase
Protein EntryMCE1_HUMAN
UniProt IDO60942
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=4; Name=1; Synonyms=HCE1, HCAP1A; IsoId=O60942-1; Sequence=Displayed; Name=2; Synonyms=HCE1A; IsoId=O60942-2; Sequence=VSP_003202; Name=3; Synonyms=HCE1B; IsoId=O60942-3; Sequence=VSP_003202, VSP_003203; Name=4; Synonyms=HCAP1B; IsoId=O60942-4; Sequence=VSP_003204;
Catalytic ActivityA 5'-phosphopolynucleotide + H(2)O = a polynucleotide + phosphate.
Catalytic ActivityGTP + (5')pp-Pur-mRNA = diphosphate + G(5')ppp-Pur-mRNA.
FunctionBifunctional mRNA-capping enzyme exhibiting RNA 5'- triphosphatase activity in the N-terminal part and mRNA guanylyltransferase activity in the C-terminal part. Catalyzes the first two steps of cap formation: by removing the gamma-phosphate from the 5'-triphosphate end of nascent mRNA to yield a diphosphate end, and by transferring the gmp moiety of GTP to the 5'-diphosphate terminus. {ECO:0000269|PubMed:21636784, ECO:0000269|PubMed:9473487, ECO:0000269|PubMed:9512541}.
MiscellaneousIsoform 2 to isoform 4 lack mRNA 5'- guanylyltransferase activity due to disruptions of the GTase domain.
SimilarityIn the C-terminal section; belongs to the eukaryotic GTase family. {ECO:0000305}.
SimilarityIn the N-terminal section; belongs to the non-receptor class of the protein-tyrosine phosphatase family. {ECO:0000305}.
Subcellular LocationNucleus {ECO:0000250}.
SubunitInteracts with POLR2A (via C-terminus); this enhances guanylyltransferase activity. Binds (via GTase domain) to the elongating phosphorylated form of RNA polymerase II; can form direct interactions with the phosphorylated POLR2A C-terminal domain and indirect interactions via bound RNA (By similarity). Interacts with SUPT5H and RNMT. Interacts with HIV-1 Tat. {ECO:0000250, ECO:0000269|PubMed:10421630, ECO:0000269|PubMed:11278368, ECO:0000269|PubMed:9705270}.
Tissue SpecificityIsoform 1 and isoform 4 (at a lesser extent) are expressed in cerebrum, cerebellum, thyroid, lung, heart, liver, kidney, spleen, large intestine, testis, skin and muscle.
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