Selective targeting of distinct active site nucleophiles by irreversible SRC-family kinase inhibitors.

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Gushwa NN, Kang S, Chen J, Taunton J

Selective targeting of distinct active site nucleophiles by irreversible SRC-family kinase inhibitors.

J Am Chem Soc. 2012 Dec 19;134(50):20214-7. doi: 10.1021/ja310659j. Epub 2012 Dec 4.

PubMed ID

23190395 [ View in PubMed

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Abstract

Src-family tyrosine kinases play pivotal roles in human physiology and disease, and several drugs that target members of this family are in clinical use. None of these drugs appear to discriminate among closely related kinases. However, assessing their selectivity toward endogenous kinases in living cells remains a significant challenge. Here, we report the design of two Src-directed chemical probes, each consisting of a nucleoside scaffold with a 5'-electrophile. A 5'-fluorosulfonylbenzoate (1) reacts with the conserved catalytic lysine (Lys295) and shows little discrimination among related kinases. By contrast, a 5'-vinylsulfonate (2) reacts with a poorly conserved, proximal cysteine (Cys277) found in three Src-family and six unrelated kinases. Both 1 and 2 bear an alkyne tag and efficiently label their respective endogenous kinase targets in intact cells. Using 1 as a competitive probe, we determined the extent to which ponatinib, a clinical Bcr-Abl inhibitor, targets Src-family kinases. Remarkably, while ponatinib had little effect on endogenous Fyn or Src, it potently blocked the critical T-cell kinase, Lck. Probes 1 and 2 thus enable competitive profiling versus distinct kinase subsets in living cells.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Ponatinib	Tyrosine-protein kinase Lck	Protein	Humans	Unknown	Inhibitor	Details