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Kraichely KN, Clinkscales SE, Hendy CM, Mendoza EA, Parnham S, Giuliano MW. Minimal Increments of Hydrophobic Collapse within the N-Terminus of the Neuropeptide Galanin. Biochemistry 2022; 61:1151-1166. [PMID: 35622960 DOI: 10.1021/acs.biochem.2c00141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The neuropeptide galanin has a 35-year history as an intriguing target in drug design owing to its implication as a potential anticonvulsant and neuronal trophic factor among many other therapeutically interesting functions including analgesia and mood alteration. In this study, we report the structural characterization of three synthetic fragments of the galanin N-terminus in buffered aqueous solution: hGal(2-12)KK, hGal(1-12)KK, and hGal(1-17)KK. High-field two-dimensional 1H-1H nuclear magnetic resonance (NMR) data were acquired for these fragments and used to derive distance restraints. We further utilized modified hydrogen bonding and dihedral restraints to reflect chemical shift patterns in the data, which revealed the signature of a weakly folded helix. Together, these sets of restraints were used to generate NMR structures of all three fragments, which depict a core of hydrophobic residues that cluster together regardless of the presence of a helical structure, and correspond to residues in the N-terminus of galanin that have been previously shown to be critical for binding its receptors. The helical structure only appears following the inclusion of Gly(1) in the sequence, and at longer sequence lengths, unlike many other peptides, the helix does not propagate. Rather, a few turns of poorly ordered helix appear to be a secondary consequence of clusters of hydrophobic sidechains that are conserved across all of the peptides in this study; the helices themselves appear ordered as a consequence of this clustering, and these clusters compare directly to those observed recently to make contacts between galanin and two of its receptor subtypes. Collapsed hydrophobic residues therefore organize and compose the functional core of human galanin and raise interesting questions about the nature of the conformational order in ligands that bind cell surface receptors.
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Affiliation(s)
- Katelyn N Kraichely
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424, United States
| | - Sarah E Clinkscales
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424, United States
| | - Cecilia M Hendy
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424, United States
| | - Eric A Mendoza
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424, United States
| | - Stuart Parnham
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, United States
| | - Michael W Giuliano
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424, United States
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Waybright JM, Clinkscales SE, Barnash KD, Budziszewski GR, Rectenwald JM, Chiarella AM, Norris-Drouin JL, Cholensky SH, Pearce KH, Herring LE, McGinty RK, Hathaway NA, James LI. A Peptidomimetic Ligand Targeting the Chromodomain of MPP8 Reveals HRP2's Association with the HUSH Complex. ACS Chem Biol 2021; 16:1721-1736. [PMID: 34415726 DOI: 10.1021/acschembio.1c00429] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The interpretation of histone post-translational modifications (PTMs), specifically lysine methylation, by specific classes of "reader" proteins marks an important aspect of epigenetic control of gene expression. Methyl-lysine (Kme) readers often regulate gene expression patterns through the recognition of a specific Kme PTM while participating in or recruiting large protein complexes that contain enzymatic or chromatin remodeling activity. Understanding the composition of these Kme-reader-containing protein complexes can serve to further our understanding of the biological roles of Kme readers, while small molecule chemical tools can be valuable reagents in interrogating novel protein-protein interactions. Here, we describe our efforts to target the chromodomain of M-phase phosphoprotein 8 (MPP8), a member of the human silencing hub (HUSH) complex and a histone 3 lysine 9 trimethyl (H3K9me3) reader that is vital for heterochromatin formation and has specific roles in cancer metastasis. Utilizing a one-bead, one-compound (OBOC) combinatorial screening approach, we identified UNC5246, a peptidomimetic ligand capable of interacting with the MPP8 chromodomain in the context of the HUSH complex. Additionally, a biotinylated derivative of UNC5246 facilitated chemoproteomics studies which revealed hepatoma-derived growth factor-related protein 2 (HRP2) as a novel protein associated with MPP8. HRP2 was further shown to colocalize with MPP8 at the E-cadherin gene locus, suggesting a possible role in cancer cell plasticity.
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Affiliation(s)
- Jarod M. Waybright
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Sarah E. Clinkscales
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | | | - Gabrielle R. Budziszewski
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Justin M. Rectenwald
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Anna M. Chiarella
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jacqueline L. Norris-Drouin
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Stephanie H. Cholensky
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Kenneth H. Pearce
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Laura E. Herring
- UNC Proteomics Core Facility, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Robert K. McGinty
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- UNC Proteomics Core Facility, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Nathaniel A. Hathaway
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Lindsey I. James
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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MacDonald IA, Butler KV, Herring LE, Clinkscales SE, Yelagandula R, Stecher K, Bell O, Graves LM, Jin J, Hathaway NA. Pathway-Based High-Throughput Chemical Screen Identifies Compounds That Decouple Heterochromatin Transformations. SLAS Discov 2019; 24:802-816. [PMID: 31145866 DOI: 10.1177/2472555219849838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Heterochromatin protein 1 (HP1) facilitates the formation of repressive heterochromatin domains by recruiting histone lysine methyltransferase enzymes to chromatin, resulting in increased levels of histone H3K9me3. To identify chemical inhibitors of the HP1-heterochromatin gene repression pathway, we combined a cell-based assay that utilized chemical-mediated recruitment of HP1 to an endogenous active gene with high-throughput flow cytometry. Here we characterized small molecule inhibitors that block HP1-mediated heterochromatin formation. Our lead compounds demonstrated dose-dependent inhibition of HP1-stimulated gene repression and were validated in an orthogonal cell-based system. One lead inhibitor was improved by a change in stereochemistry, resulting in compound 2, which was further used to decouple the inverse relationship between H3K9 and H3K4 methylation states. We identified molecular components that bound compound 2, either directly or indirectly, by chemical affinity purification with a biotin-tagged derivative, followed by quantitative proteomic techniques. In summary, our pathway-based chemical screening approach resulted in the discovery of new inhibitors of HP1-mediated heterochromatin formation while identifying exciting new molecular interactions in the pathway to explore in the future. This modular platform can be expanded to test a wide range of chromatin modification pathways yielding inhibitors that are cell permeable and function in a physiologically relevant setting.
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Affiliation(s)
- Ian A MacDonald
- 1 The Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kyle V Butler
- 2 Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Laura E Herring
- 3 Department of Pharmacology, UNC Michael Hooker Proteomics Core Facility, University of North Carolina, Chapel Hill, NC, USA
| | - Sarah E Clinkscales
- 1 The Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ramesh Yelagandula
- 4 Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Karin Stecher
- 4 Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna Biocenter (VBC), Vienna, Austria
| | - Oliver Bell
- 4 Institute of Molecular Biotechnology of the Austrian Academy of Science (IMBA), Vienna Biocenter (VBC), Vienna, Austria.,5 Department of Biochemistry and Molecular Medicine, University of Southern California, Norris Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Lee M Graves
- 3 Department of Pharmacology, UNC Michael Hooker Proteomics Core Facility, University of North Carolina, Chapel Hill, NC, USA
| | - Jian Jin
- 2 Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Nathaniel A Hathaway
- 1 The Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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