Identification of inhibitors that target dual-specificity phosphatase 5 provide new insights into the binding requirements for the two phosphate pockets

Authors

Terrence S. Neumann, Texas Wesleyan University, Concordia UniversityFollow
Elise A. Span, Concordia University, Mequon WisconsinFollow
Kelsey S. Kalous, Concordia University, Mequon WisconsinFollow
Robert D. Bongard, Medical College of Wisconsin
Adam Gastonguay, Medical College of Wisconsin
Michael A. Lepley, Medical College of Wisconsin
Raman G. Kutty, Medical College of Wisconsin
Jaladhi Nayak, Medical College of Wisconsin
Chris Bohl, Concordia University, Mequon Wisconsin
Rachel G. Lange, Concordia University, Mequon Wisconsin
Majher I. SarkerFollow
Marat R. TalipovFollow
Rajendra Rathore, Marquette UniversityFollow
Ramani Ramchandran, Medical College of Wisconsin
Daniel S. Sem, Concordia University, Mequon WisconsinFollow

Document Type

Article

Language

eng

Publication Date

8-19-2015

Publisher

BioMed Central

Source Publication

BMC Biochemistry

Source ISSN

1471-2091

Abstract

Background: Dual-specificity phosphatase-5 (DUSP5) plays a central role in vascular development and disease. We present a p-nitrophenol phosphate (pNPP) based enzymatic assay to screen for inhibitors of the phosphatase domain of DUSP5.

Methods: pNPP is a mimic of the phosphorylated tyrosine on the ERK2 substrate (pERK2) and binds the DUSP5 phosphatase domain with a Km of 7.6 ± 0.4 mM. Docking followed by inhibitor verification using the pNPP assay identified a series of polysulfonated aromatic inhibitors that occupy the DUSP5 active site in the region that is likely occupied by the dual-phosphorylated ERK2 substrate tripeptide (pThr-Glu-pTyr). Secondary assays were performed with full length DUSP5 with ERK2 as substrate.

Results: The most potent inhibitor has a naphthalene trisulfonate (NTS) core. A search for similar compounds in a drug database identified suramin, a dimerized form of NTS. While suramin appears to be a potent and competitive inhibitor (25 ± 5 μM), binding to the DUSP5 phosphatase domain more tightly than the monomeric ligands of which it is comprised, it also aggregates. Further ligand-based screening, based on a pharmacophore derived from the 7 Å separation of sulfonates on inhibitors and on sulfates present in the DUSP5 crystal structure, identified a disulfonated and phenolic naphthalene inhibitor (CSD3 _2320) with IC50 of 33 μM that is similar to NTS and does not aggregate.

Conclusions: The new DUSP5 inhibitors we identify in this study typically have sulfonates 7 Å apart, likely positioning them where the two phosphates of the substrate peptide (pThr-Glu-pTyr) bind, with one inhibitor also positioning a phenolic hydroxyl where the water nucleophile may reside. Polysulfonated aromatic compounds do not commonly appear in drugs and have a tendency to aggregate. One FDA-approved polysulfonated drug, suramin, inhibits DUSP5 and also aggregates. Docking and modeling studies presented herein identify polysulfonated aromatic inhibitors that do not aggregate, and provide insights to guide future design of mimics of the dual-phosphate loops of the ERK substrates for DUSPs.

Keywords: DUSP5, Phosphatase, Drug discovery, Docking, Suramin, Vascular anomalies

Comments

Published version. BMC Biochemistry, Vol. 16, No. 19 (2015). DOI. © 2015 BioMed Central. Used with permission.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Neumann, Terrence S.; Span, Elise A.; Kalous, Kelsey S.; Bongard, Robert D.; Gastonguay, Adam; Lepley, Michael A.; Kutty, Raman G.; Nayak, Jaladhi; Bohl, Chris; Lange, Rachel G.; Sarker, Majher I.; Talipov, Marat R.; Rathore, Rajendra; Ramchandran, Ramani; and Sem, Daniel S., "Identification of inhibitors that target dual-specificity phosphatase 5 provide new insights into the binding requirements for the two phosphate pockets" (2015). Chemistry Faculty Research and Publications. 902.
https://epublications.marquette.edu/chem_fac/902