Chemical Tools to Decipher Regulation of Phosphatases by Proline Isomerization on Eukaryotic RNA Polymerase II

Joshua E. Mayfield, Shuang Fan, Shuo Wei, Mengmeng Zhang, Bing Li, Andrew D. Ellington, Felicia A. Etzkorn, Yan Jessie Zhang

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Proline isomerization greatly impacts biological signaling but is subtle and difficult to detect in proteins. We characterize this poorly understood regulatory mechanism for RNA polymerase II carboxyl terminal domain (CTD) phosphorylation state using novel, direct, and quantitative chemical tools. We determine the proline isomeric preference of three CTD phosphatases: Ssu72 as cis-proline specific, Scp1 and Fcp1 as strongly trans-preferred. Due to this inherent characteristic, these phosphatases respond differently to enzymes that catalyze the isomerization of proline, like Ess1/Pin1. We demonstrate that this selective regulation of RNA polymerase II phosphorylation state exists within human cells, consistent with in vitro assays. These results support a model in which, instead of a global enhancement of downstream enzymatic activities, proline isomerases selectively boost the activity of a subset of CTD regulatory factors specific for cis-proline. This leads to diversified phosphorylation states of CTD in vitro and in cells. We provide the chemical tools to investigate proline isomerization and its ability to selectively enhance signaling in transcription and other biological contexts.

Original languageEnglish (US)
Pages (from-to)2405-2414
Number of pages10
JournalACS chemical biology
Volume10
Issue number10
DOIs
StatePublished - Oct 16 2015

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine

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