241 human active and 13 inactive phosphatases in total;
194 phosphatases have substrate data;
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336 protein substrates;
83 non-protein substrates;
1215 dephosphorylation interactions;
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299 KEGG pathways;
876 Reactome pathways;
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last scientific update: 11 Mar, 2019
last maintenance update: 01 Sep, 2023
Nucleus Nucleusspeckle Cytoplasm Note=May shuttle between cytoplasmand nucleus
Function (UniProt annotation)
DNA-binding protein involved in cell cycle control Mayact as a transcription activator Component of the PRP19-CDC5Lcomplex that forms an integral part of the spliceosome and isrequired for activating pre-mRNA splicing The PRP19-CDC5L complexmay also play a role in the response to DNA damage (DDR)
After transcription, eukaryotic mRNA precursors contain protein-coding exons and noncoding introns. In the following splicing, introns are excised and exons are joined by a macromolecular complex, the spliceosome. The standard spliceosome is made up of five small nuclear ribonucleoproteins (snRNPs), U1, U2, U4, U5, and U6 snRNPs, and several spliceosome-associated proteins (SAPs). Spliceosomes are not a simple stable complex, but a dynamic family of particles that assemble on the mRNA precursor and help fold it into a conformation that allows transesterification to proceed. Various spliceosome forms (e.g. A-, B- and C-complexes) have been identified.
The splicing of pre-mRNA occurs within a large, very dynamic complex, designated the 'spliceosome'. The 50-60S spliceosomes are estimated to be 40-60 nm in diameter, and have molecular weights in the range of 3-5 million kDa. Small nuclear RNAs (snRNAs) U1, U2, U4, U5, and U6, are some of the best characterized components of spliceosomes, and are known to play key roles not only in spliceosomal assembly, but also in the two catalytic steps of the splicing reaction. Over 150 proteins have been detected in spliceosomes, and only a subset of these has been characterized. The characterization, and the determination of the functions of the protein components of the spliceosome, is still work in progress.
During spliceosome assembly, the snRNAs and the spliceosomal proteins assemble on the pre-mRNA in a stepwise pathway. First the E complex forms, followed by complexes A and B; the C complex forms next and contains the products of the first step of the splicing reaction. Complexes called i and D form as a consequence of the second step of the splicing reaction, which contain the excised intron and the spliced exons, respectively