N-myristoylated c-Abl tyrosine kinase localizes to the endoplasmic reticulum upon binding to an allosteric inhibitor.

J Biol Chem 2009 Oct 13;284(42):29005-14. Epub 2009 Aug 13.

Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.

Allosteric kinase inhibitors hold promise for revealing unique features of kinases that may not be apparent using conventional ATP-competitive inhibitors. Here we explore the activity of a previously reported allosteric inhibitor of BCR-Abl kinase, GNF-2, against two cellular isoforms of Abl tyrosine kinase: one that carries a myristate in the N terminus and the other that is deficient in N-myristoylation. Our results show that GNF-2 inhibits the kinase activity of non-myristoylated c-Abl more potently than that of myristoylated c-Abl by binding to the myristate-binding pocket in the C-lobe of the kinase domain. Unexpectedly, indirect immunofluorescence reveals a translocation of myristoylated c-Abl to the endoplasmic reticulum in GNF-2-treated cells, whereas GNF-2 has no detectable effect on the localization of non-myristoylated c-Abl. These results indicate that GNF-2 competes with the NH(2)-terminal myristate for binding to the c-Abl kinase myristate-binding pocket and that the exposed myristoyl group accounts for the localization to the endoplasmic reticulum. We also demonstrate that GNF-2 can inhibit enzymatic and cellular kinase activity of Arg, a kinase highly homologous to c-Abl, which is also likely to be regulated through intramolecular binding of an NH(2)-terminal myristate lipid. These results suggest that non-ATP-competitive inhibitors, such as GNF-2, can serve as chemical tools that can discriminate between c-Abl isoform-specific behaviors.

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http://www.jbc.org/lookup/doi/10.1074/jbc.M109.026633
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http://dx.doi.org/10.1074/jbc.M109.026633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781447PMC
October 2009
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Adv. Cancer Res. 2002

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Genes Dev. 1997

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