Tyrosine phosphorylation of mammalian RNA polymerase II carboxyl-terminal domain.
AUTOR(ES)
Baskaran, R
RESUMO
The carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II is composed of tandem repeats of the consensus sequence Tyr-Ser-Pro-Thr-Ser-Pro-Ser. Phosphorylation of the CTD occurs during formation of the initiation complex and is correlated with the transition from complex assembly to elongation. Previously, serine and threonine residues within the CTD have been shown to be modified by the addition of phosphate and by the addition of O-linked GlcNAc. Our results establish that the CTD is also modified in vivo by phosphorylation on tyrosine. Furthermore, a nuclear tyrosine kinase encoded by the c-abl protooncogene phosphorylates the CTD to a high stoichiometry in vitro. Under conditions of maximum phosphorylation, approximately 30 mol of phosphate are incorporated per mol of CTD. The observation that the CTD is not phosphorylated by c-Src tyrosine kinase under identical conditions indicates that the CTD is not a substrate of all tyrosine kinases. Phosphorylation of tyrosine residues within the CTD may modulate the interaction of RNA polymerase II with the preinitiation complex and, hence, may be important in regulating gene expression.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=47943Documentos Relacionados
- Src homology 2 domain as a specificity determinant in the c-Abl-mediated tyrosine phosphorylation of the RNA polymerase II carboxyl-terminal repeated domain.
- Ubiquitination of RNA polymerase II large subunit signaled by phosphorylation of carboxyl-terminal domain
- Transcriptional activation and transformation by FosB protein require phosphorylation of the carboxyl-terminal activation domain.
- Genetic analysis of the repetitive carboxyl-terminal domain of the largest subunit of mouse RNA polymerase II.
- Cleavage/polyadenylation factor IA associates with the carboxyl-terminal domain of RNA polymerase II in Saccharomyces cerevisiae