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Ng VH, Spencer Z, Neitzel LR, Nayak A, Loberg MA, Shen C, Kassel SN, Kroh HK, An Z, Anthony CC, Bryant JM, Lawson A, Goldsmith L, Benchabane H, Hansen AG, Li J, D'Souza S, Lebensohn AM, Rohatgi R, Weiss WA, Weiss VL, Williams C, Hong CC, Robbins DJ, Ahmed Y, Lee E. The USP46 complex deubiquitylates LRP6 to promote Wnt/β-catenin signaling. Nat Commun 2023; 14:6173. [PMID: 37798301 PMCID: PMC10556042 DOI: 10.1038/s41467-023-41836-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/20/2023] [Indexed: 10/07/2023] Open
Abstract
The relative abundance of Wnt receptors plays a crucial role in controlling Wnt signaling in tissue homeostasis and human disease. While the ubiquitin ligases that ubiquitylate Wnt receptors are well-characterized, the deubiquitylase that reverses these reactions remains unclear. Herein, we identify USP46, UAF1, and WDR20 (USP46 complex) as positive regulators of Wnt signaling in cultured human cells. We find that the USP46 complex is similarly required for Wnt signaling in Xenopus and zebrafish embryos. We demonstrate that Wnt signaling promotes the association between the USP46 complex and cell surface Wnt coreceptor, LRP6. Knockdown of USP46 decreases steady-state levels of LRP6 and increases the level of ubiquitylated LRP6. In contrast, overexpression of the USP46 complex blocks ubiquitylation of LRP6 by the ubiquitin ligases RNF43 and ZNFR3. Size exclusion chromatography studies suggest that the size of the USP46 cytoplasmic complex increases upon Wnt stimulation. Finally, we show that USP46 is essential for Wnt-dependent intestinal organoid viability, likely via its role in LRP6 receptor homeostasis. We propose a model in which the USP46 complex increases the steady-state level of cell surface LRP6 and facilitates the assembly of LRP6 into signalosomes via a pruning mechanism that removes sterically hindering ubiquitin chains.
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Affiliation(s)
- Victoria H Ng
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Zachary Spencer
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH, 03755, USA
| | - Leif R Neitzel
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Anmada Nayak
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, 20057, USA
| | - Matthew A Loberg
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Chen Shen
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, 20057, USA
| | - Sara N Kassel
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Heather K Kroh
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Zhenyi An
- UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, 94158, USA
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Christin C Anthony
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Jamal M Bryant
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Amanda Lawson
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Lily Goldsmith
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Hassina Benchabane
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH, 03755, USA
| | - Amanda G Hansen
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
- STEMCELL Technologies, 1618 Station Street, Vancouver, BC, V6A 1B6, Canada
| | - Jingjing Li
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Starina D'Souza
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Andres M Lebensohn
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Rajat Rohatgi
- Departments of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - William A Weiss
- UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, 94158, USA
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Vivian L Weiss
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Charles Williams
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Charles C Hong
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - David J Robbins
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, 20057, USA
| | - Yashi Ahmed
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH, 03755, USA.
| | - Ethan Lee
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA.
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, 37232, USA.
- Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
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Spencer ZT, Ng VH, Benchabane H, Siddiqui GS, Duwadi D, Maines B, Bryant JM, Schwarzkopf A, Yuan K, Kassel SN, Mishra A, Pimentel A, Lebensohn AM, Rohatgi R, Gerber SA, Robbins DJ, Lee E, Ahmed Y. The USP46 deubiquitylase complex increases Wingless/Wnt signaling strength by stabilizing Arrow/LRP6. Nat Commun 2023; 14:6174. [PMID: 37798281 PMCID: PMC10556106 DOI: 10.1038/s41467-023-41843-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 09/20/2023] [Indexed: 10/07/2023] Open
Abstract
The control of Wnt receptor abundance is critical for animal development and to prevent tumorigenesis, but the mechanisms that mediate receptor stabilization remain uncertain. We demonstrate that stabilization of the essential Wingless/Wnt receptor Arrow/LRP6 by the evolutionarily conserved Usp46-Uaf1-Wdr20 deubiquitylase complex controls signaling strength in Drosophila. By reducing Arrow ubiquitylation and turnover, the Usp46 complex increases cell surface levels of Arrow and enhances the sensitivity of target cells to stimulation by the Wingless morphogen, thereby increasing the amplitude and spatial range of signaling responses. Usp46 inactivation in Wingless-responding cells destabilizes Arrow, reduces cytoplasmic accumulation of the transcriptional coactivator Armadillo/β-catenin, and attenuates or abolishes Wingless target gene activation, which prevents the concentration-dependent regulation of signaling strength. Consequently, Wingless-dependent developmental patterning and tissue homeostasis are disrupted. These results reveal an evolutionarily conserved mechanism that mediates Wnt/Wingless receptor stabilization and underlies the precise activation of signaling throughout the spatial range of the morphogen gradient.
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Affiliation(s)
- Zachary T Spencer
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Victoria H Ng
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Hassina Benchabane
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Ghalia Saad Siddiqui
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Deepesh Duwadi
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Ben Maines
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Jamal M Bryant
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Anna Schwarzkopf
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Kai Yuan
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Sara N Kassel
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Anant Mishra
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Ashley Pimentel
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA
| | - Andres M Lebensohn
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Scott A Gerber
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, 03766, USA
| | - David J Robbins
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, 20057, USA
| | - Ethan Lee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37232, USA.
| | - Yashi Ahmed
- Department of Molecular and Systems Biology and the Dartmouth Cancer Center, Geisel School of Medicine, Dartmouth College, Hanover, NH, 03755, USA.
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Hess EM, Kassel SN, Simandl G, Raddatz N, Maunze B, Hurley MM, Grzybowski M, Klotz J, Geurts A, Liu QS, Choi S, Twining RC, Baker DA. Genetic Disruption of System xc-Mediated Glutamate Release from Astrocytes Increases Negative-Outcome Behaviors While Preserving Basic Brain Function in Rat. J Neurosci 2023; 43:2349-2361. [PMID: 36788029 PMCID: PMC10072291 DOI: 10.1523/jneurosci.1525-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 01/04/2023] [Accepted: 02/02/2023] [Indexed: 02/16/2023] Open
Abstract
The importance of neuronal glutamate to synaptic transmission throughout the brain illustrates the immense therapeutic potential and safety risks of targeting this system. Astrocytes also release glutamate, the clinical relevance of which is unknown as the range of brain functions reliant on signaling from these cells hasn't been fully established. Here, we investigated system xc- (Sxc), which is a glutamate release mechanism with an in vivo rodent expression pattern that is restricted to astrocytes. As most animals do not express Sxc, we first compared the expression and sequence of the obligatory Sxc subunit xCT among major classes of vertebrate species. We found xCT to be ubiquitously expressed and under significant negative selective pressure. Hence, Sxc likely confers important advantages to vertebrate brain function that may promote biological fitness. Next, we assessed brain function in male genetically modified rats (MSxc) created to eliminate Sxc activity. Unlike other glutamatergic mechanisms, eliminating Sxc activity was not lethal and didn't alter growth patterns, telemetry measures of basic health, locomotor activity, or behaviors reliant on simple learning. However, MSxc rats exhibited deficits in tasks used to assess cognitive behavioral control. In a pavlovian conditioned approach, MSxc rats approached a food-predicted cue more frequently than WT rats, even when this response was punished. In attentional set shifting, MSxc rats displayed cognitive inflexibility because of an increased frequency of perseverative errors. MSxc rats also displayed heightened cocaine-primed drug seeking. Hence, a loss of Sxc-activity appears to weaken control over nonreinforced or negative-outcome behaviors without altering basic brain function.SIGNIFICANCE STATEMENT Glutamate is essential to synaptic activity throughout the brain, which illustrates immense therapeutic potential and risk. Notably, glutamatergic mechanisms are expressed by most types of brain cells. Hence, glutamate likely encodes multiple forms of intercellular signaling. Here, we hypothesized that the selective manipulation of astrocyte to neuron signaling would alter cognition without producing widespread brain impairments. First, we eliminated activity of the astrocytic glutamate release mechanism, Sxc, in rat. This impaired cognitive flexibility and increased expression of perseverative, maladaptive behaviors. Notably, eliminating Sxc activity did not alter metrics of health or noncognitive brain function. These data add to recent evidence that the brain expresses cognition-specific molecular mechanisms that could lead to highly precise, safe medications for impaired cognition.
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Affiliation(s)
- Evan M Hess
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Sara N Kassel
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Gregory Simandl
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Nicholas Raddatz
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Brian Maunze
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Matthew M Hurley
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | | | | | | | - Qing-Song Liu
- Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - SuJean Choi
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - Robert C Twining
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
| | - David A Baker
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53233
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