Substrate Specificity of the Kinase P-TEFb towards the RNA Polymerase II C-Terminal Domain

作者：Gibbs Eric B; Laremore Tatiana N; Usher Grace A; Portz Bede; Cook Erik C; Showalter Scott A^*

来源：Biophysical Journal, 2017, 113(9): 1909-1911.

DOI：10.1016/j.bpj.2017.09.011

The positive transcription elongation factor b (P-TEFb) promotes transcription elongation through phosphorylation of the RNA polymerase II C-terminal domain. This process is not well understood, partly due to difficulties in determining the specificity of P-TEFb toward the various heptad repeat motifs within the C-terminal domain. A simple assay using mass spectrometry was developed to identify the substrate specificity of the Drosophila melanogaster P-TEFb (DmP-TEFb) in vitro. This assay demonstrated that DmP-TEFb preferentially phosphorylates Ser5 and, surprisingly, that pre-phosphorylation or conserved amino acid variation at the 7-position in the heptad can alter DmP-TEFb specificity, leading to the creation of distinct double-phosphorylation marks.

• 出版日期2017-11-7