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Updated: May 21, 2026
12:26
Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
Structural and kinetic analysis of prolyl-isomerization/phosphorylation cross-talk in the CTD code
Mengmeng Zhang1, Xiaodong J Wang, Xi Chen
1Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA.
ACS Chemical Biology
|June 8, 2012
Summary
This study reveals cross-talk between proline isomerization and phosphorylation in RNA polymerase II transcription. Pin1
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- The C-terminal domain (CTD) of RNA polymerase II regulates transcription via serine phosphorylation and proline isomerization.
- Cross-talk between these regulatory mechanisms has been difficult to demonstrate experimentally.
- Pin1, a phosphorylation-specific peptidyl-prolyl isomerase, targets CTD phospho-Ser/Thr-Pro motifs.
Purpose of the Study:
- To provide structural and kinetic evidence for cross-talk between prolyl isomerization and phosphorylation in CTD regulation.
- To investigate the role of Pin1 in this regulatory interplay.
Main Methods:
- Determined crystal structures of Pin1 bound to cis- and trans-locked alkene isosteres mimicking pSer/Thr-Pro motifs.
- Utilized kinetic assays to assess the impact of Pin1 on phosphatase activity.
Main Results:
- Confirmed cis- and trans-locked alkene isosteres as effective mimics of peptide-protein interactions.
- Demonstrated that Pin1 differentially affects the dephosphorylation rates by Scp1 and Ssu72 phosphatases.
- Showed that Pin1's modulation of proline isomerization kinetically impacts CTD signal transduction.
Conclusions:
- Prolyl isomerization and phosphorylation are functionally linked in CTD-mediated transcription regulation.
- Pin1 plays a key role in mediating this cross-talk.
- Modulation of proline isomerization by Pin1 influences phosphatase specificity and activity, impacting transcription.
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