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Schonbrun AR, Resh MD. Hedgehog acyltransferase catalyzes a random sequential reaction and utilizes multiple fatty acyl-CoA substrates. J Biol Chem 2022; 298:102422. [PMID: 36030053 PMCID: PMC9513256 DOI: 10.1016/j.jbc.2022.102422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/17/2022] Open
Abstract
Sonic hedgehog (Shh) signaling is a key component of embryonic development and is a driving force in several cancers. Hedgehog acyltransferase (Hhat), a member of the membrane-bound O-acyltransferase family of enzymes, catalyzes the attachment of palmitate to the N-terminal cysteine of Shh, a posttranslation modification critical for Shh signaling. The activity of Hhat has been assayed in cells and in vitro, and cryo-EM structures of Hhat have been reported, yet several unanswered questions remain regarding the enzyme’s reaction mechanism, substrate specificity, and the impact of the latter on Shh signaling. Here, we present an in vitro acylation assay with purified Hhat that directly monitors attachment of a fluorescently tagged fatty acyl chain to Shh. Our kinetic analyses revealed that the reaction catalyzed by Hhat proceeds through a random sequential mechanism. We also determined that Hhat can utilize multiple fatty acyl-CoA substrates for fatty acid transfer to Shh, with comparable affinities and turnover rates for myristoyl-CoA, palmitoyl-CoA, palmitoleoyl-CoA, and oleoyl-CoA. Furthermore, we investigated the functional consequence of differential fatty acylation of Shh in a luciferase-based Shh reporter system. We found that the potency of the signaling response in cells was higher for Shh acylated with saturated fatty acids compared to monounsaturated fatty acids. These findings demonstrate that Hhat can attach fatty acids other than palmitate to Shh and suggest that heterogeneous fatty acylation has the potential to impact Shh signaling in the developing embryo and/or cancer cells.
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Affiliation(s)
- Adina R Schonbrun
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY; Gerstner Sloan Kettering Graduate School
| | - Marilyn D Resh
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY; Gerstner Sloan Kettering Graduate School; Biochemistry, Cell Biology and Molecular Biology Graduate Program, Weill-Cornell Graduate School of Medical Sciences, New York, NY.
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Ciulla DA, Wagner AG, Xinyue L, Cooper CL, Jorgensen MT, Wang C, Goyal P, Banavali NK, Pezzullo J, Giner JL, Callahan BP. Sterol A-ring plasticity in hedgehog protein cholesterolysis supports a primitive substrate selectivity mechanism. Chem Commun (Camb) 2019; 55:1829-1832. [PMID: 30672911 PMCID: PMC6365966 DOI: 10.1039/c8cc09729a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cholesterolysis of Hedgehog family proteins couples endoproteolysis to protein C-terminal sterylation. The transformation is self-catalyzed by HhC, a partially characterized enzymatic domain found in precursor forms of Hedgehog. Here we explore spatial ambiguity in sterol recognition by HhC, using a trio of derivatives where the sterol A-ring is contracted, fused, or distorted. Sterylation assays indicate that these geometric variants react as substrates with relative activity: cholesterol, 1.000 > A-ring contracted, 0.100 > A-ring fused, 0.020 > A-ring distorted, 0.005. Experimental results and computational sterol docking into the first HhC homology model suggest a partially unstructured binding site with substrate recognition governed in large part by hydrophobic interactions.
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Affiliation(s)
- Daniel A. Ciulla
- Chemistry Department, Binghamton University, Binghamton, New York 13902, USA
| | - Andrew G. Wagner
- Chemistry Department, Binghamton University, Binghamton, New York 13902, USA
| | - Liu Xinyue
- Biology Department, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Courtney L. Cooper
- Chemistry Department, Binghamton University, Binghamton, New York 13902, USA
| | | | - Chunyu Wang
- Biology Department, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Puja Goyal
- Chemistry Department, Binghamton University, Binghamton, New York 13902, USA
| | - Nilesh K. Banavali
- NYS Department of Health, ESP C419B, Biggs Laboratory, Wadsworth Center, Empire State Plaza, Albany, New York 12201-0509, USA
| | - John Pezzullo
- Department of Chemistry, SUNY-ESF, Syracuse, New York 13210, USA
| | - José-Luis Giner
- Department of Chemistry, SUNY-ESF, Syracuse, New York 13210, USA
| | - Brian P. Callahan
- Chemistry Department, Binghamton University, Binghamton, New York 13902, USA
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Bordeau BM, Ciulla DA, Callahan BP. Hedgehog Proteins Consume Steroidal CYP17A1 Antagonists: Potential Therapeutic Significance in Advanced Prostate Cancer. ChemMedChem 2016; 11:1983-6. [PMID: 27435344 DOI: 10.1002/cmdc.201600238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/29/2016] [Indexed: 12/21/2022]
Abstract
Abiraterone, a potent inhibitor of the human enzyme CYP17A1 (cytochrome P450c17), provides a last line of defense against ectopic androgenesis in advanced prostate cancer. Herein we report an unprecedented off-target interaction between abiraterone and oncogenic hedgehog proteins. Our experiments indicate that abiraterone and its structural congener, galeterone, can replace cholesterol as a substrate in a specialized biosynthetic event of hedgehog proteins, known as cholesterolysis. The off-target reaction generates covalent hedgehog-drug conjugates. Cell-based reporter assays indicate that these conjugates activate hedgehog signaling when present in the low nanomolar range. Because hedgehog signaling is implicated in prostate cancer progression, and abiraterone is administered to treat advanced stages of the disease, this off-target interaction may have therapeutic significance.
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Affiliation(s)
- Brandon M Bordeau
- Chemistry Department, State University of New York at Binghamton, 4400 Vestal Parkway East, Binghamton, NY, 13902, USA
| | - Daniel A Ciulla
- Chemistry Department, State University of New York at Binghamton, 4400 Vestal Parkway East, Binghamton, NY, 13902, USA
| | - Brian P Callahan
- Chemistry Department, State University of New York at Binghamton, 4400 Vestal Parkway East, Binghamton, NY, 13902, USA.
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Callahan BP, Wang C. Hedgehog Cholesterolysis: Specialized Gatekeeper to Oncogenic Signaling. Cancers (Basel) 2015; 7:2037-53. [PMID: 26473928 PMCID: PMC4695875 DOI: 10.3390/cancers7040875] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/22/2015] [Accepted: 09/28/2015] [Indexed: 12/16/2022] Open
Abstract
Discussions of therapeutic suppression of hedgehog (Hh) signaling almost exclusively focus on receptor antagonism; however, hedgehog's biosynthesis represents a unique and potentially targetable aspect of this oncogenic signaling pathway. Here, we review a key biosynthetic step called cholesterolysis from the perspectives of structure/function and small molecule inhibition. Cholesterolysis, also called cholesteroylation, generates cholesterol-modified Hh ligand via autoprocessing of a hedgehog precursor protein. Post-translational modification by cholesterol appears to be restricted to proteins in the hedgehog family. The transformation is essential for Hh biological activity and upstream of signaling events. Despite its decisive role in generating ligand, cholesterolysis remains conspicuously unexplored as a therapeutic target.
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Affiliation(s)
- Brian P Callahan
- Chemistry Department, Binghamton University 4400 Vestal Parkway East, Binghamton, NY 13902, USA.
| | - Chunyu Wang
- Biology Department, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA.
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Palm W, Swierczynska MM, Kumari V, Ehrhart-Bornstein M, Bornstein SR, Eaton S. Secretion and signaling activities of lipoprotein-associated hedgehog and non-sterol-modified hedgehog in flies and mammals. PLoS Biol 2013; 11:e1001505. [PMID: 23554573 PMCID: PMC3595218 DOI: 10.1371/journal.pbio.1001505] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 01/31/2013] [Indexed: 12/13/2022] Open
Abstract
Hedgehog (Hh) proteins control animal development and tissue homeostasis. They activate gene expression by regulating processing, stability, and activation of Gli/Cubitus interruptus (Ci) transcription factors. Hh proteins are secreted and spread through tissue, despite becoming covalently linked to sterol during processing. Multiple mechanisms have been proposed to release Hh proteins in distinct forms; in Drosophila, lipoproteins facilitate long-range Hh mobilization but also contain lipids that repress the pathway. Here, we show that mammalian lipoproteins have conserved roles in Sonic Hedgehog (Shh) release and pathway repression. We demonstrate that lipoprotein-associated forms of Hh and Shh specifically block lipoprotein-mediated pathway inhibition. We also identify a second conserved release form that is not sterol-modified and can be released independently of lipoproteins (Hh-N*/Shh-N*). Lipoprotein-associated Hh/Shh and Hh-N*/Shh-N* have complementary and synergistic functions. In Drosophila wing imaginal discs, lipoprotein-associated Hh increases the amount of full-length Ci, but is insufficient for target gene activation. However, small amounts of non-sterol-modified Hh synergize with lipoprotein-associated Hh to fully activate the pathway and allow target gene expression. The existence of Hh secretion forms with distinct signaling activities suggests a novel mechanism for generating a diversity of Hh responses.
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Affiliation(s)
- Wilhelm Palm
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Marta M. Swierczynska
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Department of Internal Medicine III, Carl Gustav Carus Medical School, Technical University of Dresden, Dresden, Germany
| | - Veena Kumari
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Monika Ehrhart-Bornstein
- Department of Internal Medicine III, Carl Gustav Carus Medical School, Technical University of Dresden, Dresden, Germany
| | - Stefan R. Bornstein
- Department of Internal Medicine III, Carl Gustav Carus Medical School, Technical University of Dresden, Dresden, Germany
| | - Suzanne Eaton
- Max-Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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Detection of canonical hedgehog signaling in breast cancer by 131-iodine-labeled derivatives of the sonic hedgehog protein. J Biomed Biotechnol 2012; 2012:639562. [PMID: 22811598 PMCID: PMC3395403 DOI: 10.1155/2012/639562] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/23/2012] [Accepted: 05/07/2012] [Indexed: 01/09/2023] Open
Abstract
Activation of hedgehog (HH) pathway signaling is observed in many tumors. Due to a feedback loop, the HH receptor Patched (PTCH-1) is overexpressed in tumors with activated HH signaling. Therefore, we sought to radiolabel the PTCH-1 ligand sonic (SHH) for detection of cancer cells with canonical HH activity. Receptor binding of 131I-SHH was increased in cell lines with high HH pathway activation. Our findings also show that PTCH-1 receptor expression is decreased upon treatment with HH signaling inhibitors, and receptor binding of 131I-SHH is significantly decreased following treatment with cyclopamine. In vivo imaging and biodistribution studies revealed significant accumulation of 131I-SHH within tumor tissue as compared to normal organs. Tumor-to-muscle ratios were approximately 8 : 1 at 5 hours, while tumor to blood and tumor to bone were 2 : 1 and 5 : 1, respectively. Significant uptake was also observed in liver and gastrointestinal tissue. These studies show that 131I-SHH is capable of in vivo detection of breast tumors with high HH signaling. We further demonstrate that the hedgehog receptor PTCH-1 is downregulated upon treatment with hedgehog inhibitors. Our data suggests that radiolabeled SHH derivatives may provide a method to determine response to SHH-targeted therapies.
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Wang Q, Huang C, Zeng F, Xue M, Zhang X. Activation of the Hh pathway in periosteum-derived mesenchymal stem cells induces bone formation in vivo: implication for postnatal bone repair. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:3100-11. [PMID: 20971735 DOI: 10.2353/ajpath.2010.100060] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
While the essential role of periosteum in cortical bone repair and regeneration is well established, the molecular pathways that control the early osteogenic and chondrogenic differentiation of periosteal stem/progenitor cells during repair processes are unclear. Using a murine segmental bone graft transplantation model, we isolated a population of early periosteum-callus-derived mesenchymal stem cells (PCDSCs) from the healing autograft periosteum. These cells express typical mesenchymal stem cell markers and are capable of differentiating into osteoblasts, adipocytes, and chondrocytes. Characterization of these cells demonstrated that activation of the hedgehog (Hh) pathway effectively promoted osteogenic and chondrogenic differentiation of PCDSCs in vitro and induced bone formation in vivo. To determine the role of the Hh pathway in adult bone repair, we deleted Smoothened (Smo), the receptor that transduces all Hh signals at the onset of bone autograft repair via a tamoxifen-inducible RosaCreER mouse model. We found that deletion of Smo markedly reduced osteogenic differentiation of isolated PCDSCs and further resulted in a near 50% reduction in periosteal bone callus formation at the cortical bone junction as determined by MicroCT and histomorphometric analyses. These data strongly suggest that the Hh pathway plays an important role in adult bone repair via enhancing differentiation of periosteal progenitors and that activation of the Hh pathway at the onset of healing could be beneficial for repair and regeneration.
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Affiliation(s)
- Qun Wang
- Center for Musculoskeletal Research, University of Rochester, School of Medicine and Dentistry, Rochester, New York 14642, USA
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