scholarly journals Toward selective inactivation of protein tyrosine phosphatase 1B via exo-affinity labeling agents

2014 ◽  
Author(s):  
◽  
Andrea Hicks Cummings
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Type Ii Diabetes ◽  
Drug Target ◽  
Tyrosine Phosphatase ◽  
Affinity Labeling ◽  
Protein Tyrosine Phosphatase 1B ◽  
Protein Signaling ◽  
Protein Targets ◽  
Protein Tyrosine ◽  
Obesity And Cancer

Exo-affinity labeling agents are compounds that achieve selectivity by modifying non-catalytic residues in a protein. They have been utilized as tools in molecular biology and to make successful drugs for protein targets. Protein tyrosine phosphatase 1B (PTP1B) is a validated drug target for type II diabetes, obesity and cancer. However, no compounds have been FDA approved for PTP1B due to selectivity and bioavailability issues with traditional compounds. We propose that exo-affinity labeling agents can be used to achieve selectivity in PTP1B. In this work we have designed, synthesized, and characterized the first exo-affinity for PTP1B. Using this work we can design better exo-affinity labeling agents that can be selective for PTP1B. This may have implications on drug design and general knowledge of protein signaling pathways.

Synthesis and properties of small molecules designed to covalently capture native and oxidized forms of protein tyrosine phosphatase 1B (PTP1B)

2016 ◽  
Author(s):  
◽  
Kasi Viswanatharaju Ruddraraju
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Active Site ◽  
Tyrosine Phosphatase ◽  
Covalent Modification ◽  
Affinity Labeling ◽  
Protein Tyrosine Phosphatase 1B ◽  
University Of Missouri ◽  
Protein Tyrosine ◽  
Enzyme Active Site ◽  
Carbon Nucleophiles

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Protein tyrosine phosphatase 1B (PTP1B) is a validated target for the treatment of type 2 diabetes and obesity. The discovery of selective inhibitors with drug-like properties has proven to be challenging because there are [about]80 PTP family members that share a similar and positively charged active site. To overcome these challenges, we have pursued two novel approaches for the covalent inactivation of PTP1B. Exo-affinity labeling agents exploit covalent reactions with amino acids outside the enzyme active site to gain both affinity and selectivity. We prepared several affinity labeling agents using a 12-step convergent synthesis. Enzyme assays revealed that some of these agents are capable of inactivating the enzyme by covalent modification. In another project, we prepared a low molecular weight mimic of the oxidized form of PTP1B that is generated in cells, during insulin signaling events. Seeking molecules capable of covalent capture of oxidized PTP1B, we treated this chemical model with several carbon nucleophiles, such as 1,3-diketones and sulfone-stabilized carbon anions. These carbon nucleophiles readily reacted with the model compound, under mild conditions to give stable adducts. Inactivation experiments revealed that 1,3-diketones are capable of inactivating the oxidized PTP1B at micromolar concentrations.

On the kinetics and mechanisms associated with covalent inactivation of protein tyrosine phosphatase 1b (ptp1b) by dietary phytochemicals and affinity labeling molecules

2015 ◽  
Author(s):  
◽  
Sarah M. Lewis
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
General Structure ◽  
Tyrosine Phosphatase ◽  
Covalent Attachment ◽  
Nucleophilic Attack ◽  
Affinity Labeling ◽  
Breakdown Product ◽  
Protein Tyrosine Phosphatase 1B ◽  
University Of Missouri ◽  
Protein Tyrosine

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Phytochemical are compounds that occur naturally in plants. These compounds are what give many foods their distinct color and flavor. There are five major types of phytochemicals; phenolic compounds, terepenes, betalains, glucosinolates, and organic acids. This work focused on a breakdown product of glucosinolates, isothiocyanates, which are found in Brassica, and are common in most diets. Isothiocyanates have a general structure of R-N=C=S, with an electron deficient carbon that is subject to nucleophilic attack by thiols to produce dithiocarbamates. This work investigated the inactivation of protein tyrosine phosphatase 1B by isothocyanates, and found that this occurs via a covalent, reversible mechanism. Affinity labels were originally used to elucidate the active site of many proteins. More recently however, much attention has been given to the use of an affinity label to covalently label a protein. It is with this technique of covalent attachment to our protein of interest that an exo-affinity labeling molecule was designed. The kinetics, stability, and mechanism of these molecules with protein tyrosine phosphatase 1B are evaluated here.

scholarly journals Minimally disruptive optical control of protein tyrosine phosphatase 1B

2019 ◽  
Author(s):  
Akarawin Hongdusit ◽  
Peter H. Zwart ◽  
Banumathi Sankaran ◽  
Jerome M. Fox
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Tyrosine Kinases ◽  
Regulatory Element ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Protein Tyrosine Phosphatase 1B ◽  
Post Translational Modifications ◽  
Protein Tyrosine ◽  
Important Regulator ◽  
Obesity And Cancer

ABSTRACTProtein tyrosine phosphatases regulate a myriad of essential subcellular signaling events, yet they remain difficult to study in their native biophysical context. Here we develop a minimally disruptive optical approach to control protein tyrosine phosphatase 1B (PTP1B)—an important regulator of receptor tyrosine kinases and a therapeutic target for the treatment of diabetes, obesity, and cancer—and we use that approach to probe the intracellular function of this enzyme. Our conservative architecture for photocontrol, which consists of a protein-based light switch fused to an allosteric regulatory element, preserves the native structure, activity, and subcellular localization of PTP1B, affords changes in activity that match those elicited by post-translational modifications inside the cell, and permits experimental analyses of the molecular basis of optical modulation. Findings indicate, most strikingly, that small changes in the activity of PTP1B can cause large shifts in the phosphorylation states of its regulatory targets.

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