The C-terminal domain phosphatase and transcription elongation activities of FCP1 are regulated by phosphorylation.
The C-terminal domain (CTD) of the largest subunit of RNA polymerase II (RNAPII) is heavily phosphorylated during the transition from transcription initiation to the establishment of an elongation-competent transcription complex. FCP1 is the only phosphatase known to be specific for the CTD of the largest subunit of RNAPII, and its activity is believed to be required to reactivate RNAPII, so that RNAPII can enter another round of transcription. We demonstrate that FCP1 is a phosphoprotein, and that phosphorylation regulates FCP1 activities. FCP1 is phosphorylated at multiple sites in vivo. The CTD phosphatase activity of phosphorylated FCP1 is stimulated by TFIIF, whereas dephosphorylated FCP1 is not. In addition to its role in the recycling of RNAPII, FCP1 also affects transcription elongation. Phosphorylated FCP1 is more active in stimulating transcription elongation than the dephosphorylated form of FCP1. We found that only phosphorylated FCP1 can physically interact with TFIIF. We set out to purify an FCP1 kinase from HeLa cells and identified casein kinase 2, which, surprisingly, displayed a negative effect on FCP1-associated activities.
Friedl
Erika M
EM
Howard Hughes Medical Institute, Division of Nucleic Acids Research, Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
Lane
William S
WS
Erdjument-Bromage
Hediye
H
Tempst
Paul
P
Reinberg
Danny
D
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D016367:Baculoviridae / Q000378:metabolism; D001483:Base Sequence; D015153:Blotting, Western; D047390:Casein Kinase II; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D007313:Insecta; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000737:chemistry*; D010766:Phosphorylation; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000737:chemistry* / Q000378:metabolism; D014158:Transcription, Genetic
D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D012319:RNA Polymerase II; D000469:Alkaline Phosphatase; D010749:Phosphoprotein Phosphatases; C116022:carboxy-terminal domain phosphatase