Enhanced SH3/Linker Interaction Overcomes Abl Kinase Activation by Gatekeeper and Myristic Acid Binding Pocket Mutations and Increases Sensitivity to Small Molecule Inhibitors*

Panjarian, Shoghag; Iacob, Roxana E.; Chen, Shugui; Wales, Thomas E.; Engen, John R.; Smithgall, Thomas E.

doi:10.1074/jbc.m112.431312

Cited by 29 publications

(63 citation statements)

References 39 publications

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“…We present evidence that mechanisms of Abl activation, which previously relied on time-consuming eukaryotic expression systems, can be mirrored using pure recombinant proteins produced in bacteria. This approach enabled the discovery of a novel mechanism that links the allosteric regulation of the SH2 domain to two critical phosphorylation events and expanded our understanding of Abl kinase activation 37 . Although the ample availability of validated research tools, such as antibodies, kinase inhibitors and mutations, has accelerated this process, the proposed workflow and experimental approaches will facilitate future quantitative analyses of allosteric regulatory mechanisms in other tyrosine kinases.…”

Section: Discussionmentioning

confidence: 99%

The SH2 domain of Abl kinases regulates kinase autophosphorylation by controlling activation loop accessibility

et al. 2014

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The activity of protein kinases is regulated by multiple molecular mechanisms, and their disruption is a common driver of oncogenesis. A central and almost universal control element of protein kinase activity is the activation loop that utilizes both conformation and phosphorylation status to determine substrate access. In this study, we use recombinant Abl tyrosine kinases and conformation-specific kinase inhibitors to quantitatively analyse structural changes that occur after Abl activation. Allosteric SH2-kinase domain interactions were previously shown to be essential for the leukemogenesis caused by the Bcr-Abl oncoprotein. We find that these allosteric interactions switch the Abl activation loop from a closed to a fully open conformation. This enables the trans-autophosphorylation of the activation loop and requires prior phosphorylation of the SH2-kinase linker. Disruption of the SH2-kinase interaction abolishes activation loop phosphorylation. Our analysis provides a molecular mechanism for the SH2 domain-dependent activation of Abl that may also regulate other tyrosine kinases.

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Section: Discussionmentioning

confidence: 99%

The SH2 domain of Abl kinases regulates kinase autophosphorylation by controlling activation loop accessibility

et al. 2014

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“…The names and drugs may change quickly as some of the substances tested in cell lines may never reach phase I trials and some of the drugs tested in phase I trials may never reach phase II trials. One approach which may be promising is the use of ATP-binding site inhibitors of BCR-ABL (e.g., GNF-2, ABL001) [66][67][68] or the use of monoclonal antibody-based treatments such as an anti-PD-1 drug, e.g., nivolumab [69,70] currently in phase I trials.…”

Section: Prospectsmentioning

confidence: 99%

Management of chronic myeloid leukemia in blast crisis

Saußele

Silver

2015

Ann Hematol

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Due to the high efficacy of BCR-ABL tyrosine kinase inhibition (TKI) in chronic phase (CP) chronic myeloid leukemia (CML), the frequency of blast crisis (BC) is greatly reduced compared to the pre-TKI era. However, TKI treatment of BC has only marginally improved the number of favorable responses, including remissions, which for the most part have only been transitory. Occasionally, they provide a therapeutic window to perform an allogeneic stem cell transplantation (allo-SCT). The challenge remains to improve management of BC with the limited options available. We review and summarize articles pertaining to the treatment of BC CML published after 2002. Additionally, we will discuss whether there is a need for a new definition of BC and/or treatment failure.

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“…Recent work from our laboratories approached this question more directly by systematically increasing the proline content of the Abl SH2/kinase linker to enhance intramolecular SH3 engagement (69). Remarkably, myeloid cells transformed with Bcr-Abl proteins carrying high affinity linkers showed enhanced sensitivity to apoptosis induced by both imatinib and GNF-2.…”

Section: What Do Structural Studies Of the Abl Core Tell Us About Bcrmentioning

confidence: 99%

“…Although the N-cap region was disordered in the first crystal structure of the c-Abl core, a more recent structure with a modified N-cap revealed that Ser 69 (numbered according to Protein Data Bank (PDB) code 2FO0) 4 is phosphorylated and contacts the short connector joining the SH3 and SH2 domains. Mutation of Ser 69 increased Abl activity, identifying this site as a potential input for regulatory kinases (12). Additional contacts were observed between N-cap residues 65-80 and the SH2 domain, supporting the idea that the N-cap helps to clamp the SH3 and SH2 domains to the back of the kinase domain.…”

Section: The Myristoylated N-cap Is Critical For Down-regulation Of Ablmentioning

confidence: 99%

Structure and Dynamic Regulation of Abl Kinases*

Panjarian

Iacob

Chen

et al. 2013

Journal of Biological Chemistry

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The c-abl proto-oncogene encodes a unique protein-tyrosine kinase (Abl) distinct from c-Src, c-Fes, and other cytoplasmic tyrosine kinases. In normal cells, Abl plays prominent roles in cellular responses to genotoxic stress as well as in the regulation of the actin cytoskeleton. Abl is also well known in the context of Bcr-Abl, the oncogenic fusion protein characteristic of chronic myelogenous leukemia. Selective inhibitors of Bcr-Abl, of which imatinib is the prototype, have had a tremendous impact on clinical outcomes in chronic myelogenous leukemia and revolutionized the field of targeted cancer therapy. In this minireview, we focus on the structural organization and dynamics of Abl kinases and how these features influence inhibitor sensitivity. Structural Overview of the c-Abl Kinase CoreThe kinase core of the c-Abl protein has a domain organization similar to that of the Src family kinases, with sequential Src homology (SH) 3 3 and SH2 domains, an SH2/kinase linker, and a bilobed kinase domain (Fig. 1). This core is flanked by an N-terminal "cap" (N-cap) region with a signal sequence for myristoylation, which serves dual roles in regulation of kinase activity and in membrane localization. C-terminal to the kinase domain is a long region of Ͼ600 amino acids encoded by a single exon, which controls interaction of Abl with other SH3-containing proteins and the actin cytoskeleton. This region also regulates nuclear-cytoplasmic shuttling of the kinase (1-4). These key structural and regulatory features are discussed in detail below. The Myristoylated N-cap Is Critical for Down-regulation of AblThe N-cap is ϳ80 amino acids in length and is myristoylated in the 1b splice variant of Abl (5). The first crystal structure of the Abl core (residues 1-531) revealed that this N-terminal myristic acid group binds a deep hydrophobic pocket in the C-terminal lobe (C-lobe) of the kinase domain ( Fig. 1) (6). Binding of the myristoyl group into this pocket induces a bend in C-lobe helix ␣I, allowing the SH2 domain to dock onto the C-lobe of the kinase domain (Fig. 2). Interaction of the myristoylated N-cap with the C-lobe is critical to maintenance of the autoinhibited state, as mutation of the myristoylation signal sequence results in a highly active kinase (7). Interestingly, small molecules that bind to this site also modulate kinase activity, supporting an allosteric connection between this regulatory pocket and the kinase active site (8 -11).In addition to binding the C-lobe of the kinase domain, the N-cap also influences kinase regulation via the SH3 and SH2 domains. Although the N-cap region was disordered in the first crystal structure of the c-Abl core, a more recent structure with a modified N-cap revealed that Ser 69 (numbered according to Protein Data Bank (PDB) code 2FO0) 4 is phosphorylated and contacts the short connector joining the SH3 and SH2 domains. Mutation of Ser 69 increased Abl activity, identifying this site as a potential input for regulatory kinases (12). Additional contacts were observed between N...

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Enhanced SH3/Linker Interaction Overcomes Abl Kinase Activation by Gatekeeper and Myristic Acid Binding Pocket Mutations and Increases Sensitivity to Small Molecule Inhibitors*

Cited by 29 publications

References 39 publications

The SH2 domain of Abl kinases regulates kinase autophosphorylation by controlling activation loop accessibility

The SH2 domain of Abl kinases regulates kinase autophosphorylation by controlling activation loop accessibility

Management of chronic myeloid leukemia in blast crisis

Structure and Dynamic Regulation of Abl Kinases*

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