The FCP1 phosphatase interacts with RNA polymerase II and with MEP50 a component of the methylosome complex involved in the assembly of snRNP.
RNA polymerase II transcription is associated with cyclic phosphorylation of the C-terminal domain (CTD) of the large subunit of RNA polymerase II. To date, FCP1 is the only specific CTD phosphatase, which is required for general transcription and cell viability. To identify FCP1-associated proteins, we constructed a human cell line expressing epitope-tagged FCP1. In addition to RAP74, a previously identified FCP1 interacting factor, we determined that FCP1-affinity purified extracts contain RNAPII that has either a hyper- or a hypo-phosphorylated CTD. In addition, by mass spectrometry of affinity purified FCP1-associated factors, we identified a novel FCP1-interacting protein, named MEP50, a recently described component of the methylosome complex that binds to the snRNP's Sm proteins. We found that FCP1 specifically interacts with components of the spliceosomal U small nuclear ribonucleoproteins. These results suggest a putative role of FCP1 CTD-phosphatase in linking the transcription elongation with the splicing process.
Licciardo
Paolo
P
Department of Genetics, General and Molecular Biology, University of Naples Federico II, Via Mezzocannone 8, 80134 Naples, Italy.
Amente
Stefano
S
Ruggiero
Luca
L
Monti
Maria
M
Pucci
Piero
P
Lania
Luigi
L
Majello
Barbara
B
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D046911:Macromolecular Substances; D008745:Methylation; D010749:Phosphoprotein Phosphatases / Q000378:metabolism* / Q000502:physiology; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000737:chemistry / Q000378:metabolism*; D017411:Ribonucleoproteins, Small Nuclear / Q000096:biosynthesis* / Q000378:metabolism; D017381:Spliceosomes / Q000737:chemistry; D014157:Transcription Factors
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D046911:Macromolecular Substances; D010749:Phosphoprotein Phosphatases; D012319:RNA Polymerase II; D017411:Ribonucleoproteins, Small Nuclear; C116022:carboxy-terminal domain phosphatase; C478359:WDR77 protein, human; D014157:Transcription Factors