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Keedy DA, Hill ZB, Biel JT, Kang E, Rettenmaier TJ, Brandão-Neto J, Pearce NM, von Delft F, Wells JA, Fraser JS. An expanded allosteric network in PTP1B by multitemperature crystallography, fragment screening, and covalent tethering. eLife 2018; 7:36307. [PMID: 29877794 PMCID: PMC6039181 DOI: 10.7554/elife.36307] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/04/2018] [Indexed: 12/28/2022] Open
Abstract
Allostery is an inherent feature of proteins, but it remains challenging to reveal the mechanisms by which allosteric signals propagate. A clearer understanding of this intrinsic circuitry would afford new opportunities to modulate protein function. Here, we have identified allosteric sites in protein tyrosine phosphatase 1B (PTP1B) by combining multiple-temperature X-ray crystallography experiments and structure determination from hundreds of individual small-molecule fragment soaks. New modeling approaches reveal 'hidden' low-occupancy conformational states for protein and ligands. Our results converge on allosteric sites that are conformationally coupled to the active-site WPD loop and are hotspots for fragment binding. Targeting one of these sites with covalently tethered molecules or mutations allosterically inhibits enzyme activity. Overall, this work demonstrates how the ensemble nature of macromolecular structure, revealed here by multitemperature crystallography, can elucidate allosteric mechanisms and open new doors for long-range control of protein function. Proteins perform many important jobs in each of the cells in our bodies, such as transporting other molecules and helping chemical reactions to occur. The part of the protein directly involved in these tasks is called the active site. Other areas of the protein can communicate with the active site to switch the protein on or off. This method of control is known as allostery. Switching proteins on and off could help us to develop treatments for certain diseases. For example, a protein called PTP1B reduces how well cells can respond to insulin. Switching this protein off could therefore help to treat diabetes. However, much like it’s hard to guess how a light switch is wired to a light bulb without seeing behind the walls, it is hard to predict which remote areas of a protein are ‘wired’ to the active site. Keedy, Hill et al. have now used two complementary methods to examine the structure of PTP1B and find new allosteric sites. The first method captured a series of X-ray images from crystallized molecules of the protein held at different temperatures. This revealed areas of PTP1B that can move like windshield wipers to communicate with each other. The second method soaked PTP1B crystals in trays with hundreds of drug-sized molecules and assessed which sites on the protein the molecules bound to. The molecules generally bound to just a few sites of the protein. Further tests on one of these sites showed that it can communicate with the active site to turn the protein on or off. Further work will be needed to develop drugs that could treat diabetes by binding to the newly identified allosteric sites in PTP1B. More generally, the methods developed by Keedy, Hill et al. could be used to study allostery in other important proteins.
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Affiliation(s)
- Daniel A Keedy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
| | - Zachary B Hill
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
| | - Justin T Biel
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
| | - Emily Kang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States
| | - T Justin Rettenmaier
- Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | | | - Nicholas M Pearce
- Crystal and Structural Chemistry Group, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Frank von Delft
- Diamond Light Source, Didcot, United Kingdom.,Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom.,Department of Biochemistry, University of Johannesburg, Johannesburg, South Africa
| | - James A Wells
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, United States.,Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - James S Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States
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Hill ZB, Martinko AJ, Nguyen DP, Wells JA. Human antibody-based chemically induced dimerizers for cell therapeutic applications. Nat Chem Biol 2017; 14:112-117. [PMID: 29200207 PMCID: PMC6352901 DOI: 10.1038/nchembio.2529] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 10/20/2017] [Indexed: 01/27/2023]
Abstract
Chemically induced dimerizers (CIDs) have emerged as one of the most powerful tools to artificially regulate signaling pathways in cells; however, currently available CID systems lack the properties desired for use in regulating cellular therapies. Here, we report the development of human antibody-based chemically induced dimerizers (AbCIDs) from known small-molecule-protein complexes by selecting for synthetic antibodies that recognize the chemical epitope created by the bound small molecule. We demonstrate this concept by generating three antibodies that are highly selective for the BCL-xL/ABT-737 complex over BCL-xL alone. We show the potential of AbCIDs to be applied to regulating human cell therapies by using them to induce CRISPRa-mediated gene expression and to regulate CAR T-cell activation. We believe that the AbCIDs generated in this study will find application in regulating cell therapies, and that the general method of AbCID development may lead to the creation of many new and orthogonal CIDs.
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Affiliation(s)
- Zachary B Hill
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Alexander J Martinko
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, California, USA
| | - Duy P Nguyen
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - James A Wells
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California, USA
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Hill ZB, Pollock SB, Zhuang M, Wells JA. Direct Proximity Tagging of Small Molecule Protein Targets Using an Engineered NEDD8 Ligase. J Am Chem Soc 2016; 138:13123-13126. [PMID: 27626304 DOI: 10.1021/jacs.6b06828] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Identifying the protein targets of bioactive small molecules remains a major problem in the discovery of new chemical probes and therapeutics. While activity-based probes and photo-cross-linkers have had success in identifying protein targets of small molecules, each technique has limitations. Here we describe a method for direct proximity tagging of proteins that bind small molecules. We engineered a promiscuous ligase based on the NEDD8 conjugating enzyme, Ubc12, which can be covalently linked to a small molecule of interest. When target proteins bind the small molecule, they are directly labeled on surface lysines with a biotinylated derivative of the small ubiquitin homologue, NEDD8. This unique covalent tag can then be used to identify the small molecule binding proteins. Utilizing the drug dasatinib, we have shown that dasatinib-directed NEDDylation occurs for known endogenous protein binders in complex cell lysates. In addition, we have been able to improve NEDDylation efficiency through rational mutagenesis. Finally, we have shown that affinity-directed NEDDylation can be applied to two other protein-ligand interactions beyond kinases. Proximity tagging using this engineered ligase requires direct binding of the target and, thus, provides a useful and orthogonal approach to facilitate small molecule target identification.
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Affiliation(s)
- Zachary B Hill
- Department of Pharmaceutical Chemistry and ‡Department of Cellular and Molecular Pharmacology, University of California , San Francisco, California 94158, United States
| | - Samuel B Pollock
- Department of Pharmaceutical Chemistry and ‡Department of Cellular and Molecular Pharmacology, University of California , San Francisco, California 94158, United States
| | - Min Zhuang
- Department of Pharmaceutical Chemistry and ‡Department of Cellular and Molecular Pharmacology, University of California , San Francisco, California 94158, United States
| | - James A Wells
- Department of Pharmaceutical Chemistry and ‡Department of Cellular and Molecular Pharmacology, University of California , San Francisco, California 94158, United States
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Abstract
Protein kinases are essential enzymes for cellular signaling, and are often regulated by participation in protein complexes. The mitogen-activated protein kinase (MAPK) p38 is involved in multiple pathways, and its regulation depends on its interactions with other signaling proteins. However, the identification of p38-interacting proteins is challenging. For this reason, we have developed label transfer reagents (LTRs) that allow labeling of p38 signaling complexes. These LTRs leverage the potency and selectivity of known p38 inhibitors to place a photo-crosslinker and tag in the vicinity of p38 and its binding partners. Upon UV irradiation, proteins that are in close proximity to p38 are covalently crosslinked, and labeled proteins are detected and/or purified with an orthogonal chemical handle. Here we demonstrate that p38-selective LTRs selectively label a diversity of p38 binding partners, including substrates, activators, and inactivators. Furthermore, these LTRs can be used in immunoprecipitations to provide low-resolution structural information on p38-containing complexes.
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Affiliation(s)
- Simeon S Andrews
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700, USA
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Hill ZB, Perera BGK, Andrews SS, Maly DJ. Targeting diverse signaling interaction sites allows the rapid generation of bivalent kinase inhibitors. ACS Chem Biol 2012; 7:487-95. [PMID: 22148755 DOI: 10.1021/cb200387g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The identification of potent and selective modulators of protein kinase function remains a challenge, and new strategies are needed for generating these useful ligands. Here, we describe the generation of bivalent inhibitors of three unrelated protein kinases: the CAMK family kinase Pim1, the mitogen-activated protein kinase (MAPK) p38α, and the receptor tyrosine kinase (RTK) epidermal growth factor receptor (EGFR). These bivalent inhibitors consist of an ATP-competitive inhibitor that is covalently tethered to an engineered form of the self-labeling protein O(6)-alkylguanine-DNA alkyltransferase (SNAP-tag). In each example, SNAP-tag is fused to a peptide ligand that binds to a signaling interaction site of the kinase being targeted. These interactions increase the overall selectivity and potency of the bivalent inhibitors that were generated. The ability to exploit disparate binding sites in diverse kinases points to the generality of the method described. Finally, we demonstrate that ATP-competitive inhibitors that are conjugated to the bio-orthogonal tag O(4)-benzyl-2-chloro-6-aminopyrimidine (CLP) are cell-permeable. The selective labeling of SNAP-tag with CLP conjugates allows the rapid assembly of bivalent inhibitors in living cells.
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Affiliation(s)
- Zachary B. Hill
- Department
of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700,
United States
| | - B. Gayani K. Perera
- Department
of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700,
United States
| | - Simeon S. Andrews
- Department
of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700,
United States
| | - Dustin J. Maly
- Department
of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700,
United States
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Gregersen KAD, Hill ZB, Gadd JC, Fujimoto BS, Maly DJ, Chiu DT. Intracellular delivery of bioactive molecules using light-addressable nanocapsules. ACS Nano 2010; 4:7603-11. [PMID: 21117640 PMCID: PMC3075813 DOI: 10.1021/nn102345f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This paper describes a method by which molecules that are impermeable to cells are encapsulated in dye-sensitized lipid nanocapsules for delivery into cells via endocytosis. Once inside the cells, the molecules are released from the lipid nanocapsules into the cytoplasm with a single nanosecond pulse from a laser in the far red (645 nm). We demonstrate this method with the intracellular release of the second messenger IP(3) in CHO-M1 cells and report that calcium responses from the cells changed from a sustained increase to a transient spike when the average number of IP(3) released is decreased below 50 molecules per nanocapsule. We also demonstrate the delivery of a 23 kDa O(6)-alkylguanine-DNA alkyltransferase (AGT) fusion protein into Ba/F3 cells to inhibit a key player BCR-ABL in the apoptotic pathway. We show that an average of ∼8 molecules of the inhibitor is sufficient to induce apoptosis in the majority of Ba/F3 cells.
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Hill ZB, Perera BGK, Maly DJ. Bivalent inhibitors of the tyrosine kinases ABL and SRC: determinants of potency and selectivity. Mol Biosyst 2010; 7:447-56. [PMID: 21060940 DOI: 10.1039/c0mb00108b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We recently reported a chemical genetic method for generating bivalent inhibitors of protein kinases. This method relies on the use of the DNA repair enzyme O(6)-alkylguanine-DNA alkyltransferase (AGT) to display an ATP-competitive inhibitor and a ligand that targets a secondary binding domain. With this method potent and selective inhibitors of the tyrosine kinases SRC and ABL were identified. Here, we dissect the molecular determinants of the potency and selectivity of these bivalent ligands. Systematic analysis of ATP-competitive inhibitors with varying linker lengths revealed that SRC and ABL have differential sensitivities to ligand presentation. Generation of bivalent constructs that contain ligands with differential affinities for the ATP-binding sites and SH3 domains of SRC and ABL demonstrated the modular nature of inhibitors based on the AGT scaffold. Furthermore, these studies revealed that the interaction between the SH3 domain ligand and the kinase SH3 domain is the major selectivity determinant amongst closely-related tyrosine kinases. Finally, the potency of bivalent inhibitors against distinct phospho-isoforms of SRC was determined. Overall, these results provide insight into how individual ligands can be modified to provide more potent and selective bivalent inhibitors of protein kinases.
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Affiliation(s)
- Zachary B Hill
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, USA
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Abstract
We report a new chemical genetic method for creating bivalent ligands of protein kinases. The kinase inhibitors that are generated with this methodology consist of two components: (1) a synthetic, small molecule that targets the ATP-binding cleft and (2) a peptidic ligand that enhances selectivity between kinases by targeting a secondary binding domain. A key feature of these bivalent inhibitors is that they are assembled on a protein scaffold with a chemoselective protein labeling technique. The utility of this methodology is demonstrated through the generation of a panel of protein-small molecule conjugates that simultaneously target the SH1 and SH3 domains of the closely related tyrosine kinases Src and Abl. The assembled bivalent ligands are significantly more potent inhibitors of Src and Abl than either modular component alone. Importantly, these protein-small molecule conjugates show a high degree of selectivity for their intended kinase target.
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Affiliation(s)
- Zachary B Hill
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, USA
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Hill ZB, Rodovsky DB, Leger JM, Bartholomew GP. Synthesis and utilization of perylene-based n-type small molecules in light-emitting electrochemical cells. Chem Commun (Camb) 2008:6594-6. [DOI: 10.1039/b814913e] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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