chemical-inactivation-e3-ubiquitin-ligase-cereblon-pomalidomide-based

Chemical Inactivation of the E3 Ubiquitin Ligase Cereblon by Pomalidomide-based Homo-PROTACs

The immunomodulatory drugs (IMiDs) thalidomide and its analogs, lenalidomide and pomalidomide, all FDA approved drugs for the treatment of multiple ...

University of Bonn

Activity-based probes are compounds that exclusively form covalent bonds with active enzymes. They can be utilized to profile enzyme activities in vivo, to identify target enzymes and to characterize their function. The design of a new activity-based probe for matriptase, a member of the type II transmembrane serine proteases, is based on linker-connected bis-benzguanidines. An amino acid, introduced as linker, bears the coumarin fluorophore. Moreover, an incorporated phosphonate allows for a covalent interaction with the active-site serine. The resulting irreversible mode of action was demonstrated, leading to enzyme inactivation and, simultaneously, to a fluorescence labeling of matriptase. The ten-step synthetic approach to a coumarin-labeled bis-benzguanidine and its evaluation as activity-based probe for matriptase based on in-gel fluorescence and fluorescence HPLC is reported. HPLC fluorescence detection as a new application for activity-based probes for proteases is demonstrated herein for the first time.

A Fluorescent-Labeled Phosphono Bisbenzguanidine As an Activity-Based Probe for Matriptase.

Matriptase-2 is a type II transmembrane serine protease and a key regulator of systemic iron homeostasis. Since the activation mechanism and several features of the physiological role of matriptase-2 are not fully understood, there is strong need for analytical tools to perform tasks such as distinguishing active and inactive matriptase-2. For this purpose we present a short biotinylated peptide derivative with a chloromethyl ketone group, biotin-RQRR-CMK, as an activity-based probe for matriptase-2. Biotin-RQRR-CMK was kinetically characterized and exhibited a second-order rate constant of inactivation (/) of 10,800 M s towards the matriptase-2 activity in the supernatant of transfected human embryonic kidney (HEK) cells. Biotin-RQRR-CMK was able to label active matriptase-2, as visualized in western blot experiments. Pretreatment with aprotinin, an active-site directed inhibitor of serine proteases, protected matriptase-2 from the reaction with biotin-RQRR-CMK.

A Short Peptide Inhibitor as an Activity-Based Probe for Matriptase-2.

Matriptase-2 (MT2) is a membrane-anchored proteolytic enzyme. It acts as the proteolytic key regulator in human iron homeostasis. A high expression level can lead to iron overload diseases, whereas mutations in the gene encoding MT2, TMPRSS6, may result in various forms of iron deficiency anemia. Recently, MT2 has been reported as a positive prognostic factor in breast and prostate cancers. However, the exact functions of MT2 in various pathophysiological conditions are still not fully understood. In this review, we describe the synthetic tools designed and synthesized to regulate or monitor MT2 proteolytic activity and present the latest knowledge about the role of MT2 in iron homeostasis and cancer.

Article	Year
A Fluorescent-Labeled Phosphono Bisbenzguanidine As an Activity-Based Probe for Matriptase. Chemistry (Weinheim an der Bergstrasse, Germany)\| PubMed ID: 28370501	2017
A Short Peptide Inhibitor as an Activity-Based Probe for Matriptase-2. Pharmaceuticals (Basel, Switzerland)\| PubMed ID: 29883401	2018
Matriptase-2: monitoring and inhibiting its proteolytic activity. Future medicinal chemistry\| PubMed ID: 30518272	2018

Martin Mangold

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