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Banerjee A, Phillips BL, Deng Q, Seyfried NT, Pavlath GK, Vest KE, Corbett AH. Proteomic analysis reveals that wildtype and alanine-expanded nuclear poly(A)-binding protein exhibit differential interactions in skeletal muscle. J Biol Chem 2019; 294:7360-7376. [PMID: 30837270 DOI: 10.1074/jbc.ra118.007287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 02/19/2019] [Indexed: 12/22/2022] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late-onset, primarily autosomal dominant disease caused by a short GCN expansion in the PABPN1 (polyadenylate-binding protein nuclear 1) gene that results in an alanine expansion at the N terminus of the PABPN1 protein. Expression of alanine-expanded PABPN1 is linked to the formation of nuclear aggregates in tissues from individuals with OPMD. However, as with other nuclear aggregate-associated diseases, controversy exists over whether these aggregates are the direct cause of pathology. An emerging hypothesis is that a loss of PABPN1 function and/or aberrant protein interactions contribute to pathology in OPMD. Here, we present the first global proteomic analysis of the protein interactions of WT and alanine-expanded PABPN1 in skeletal muscle tissue. These data provide both insight into the function of PABPN1 in muscle and evidence that the alanine expansion alters the protein-protein interactions of PABPN1. We extended this analysis to demonstrate altered complex formation with and loss of function of TDP-43 (TAR DNA-binding protein 43), which we show interacts with alanine-expanded but not WT PABPN1. The results from our study support a model where altered protein interactions with alanine-expanded PABPN1 that lead to loss or gain of function could contribute to pathology in OPMD.
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Affiliation(s)
| | - Brittany L Phillips
- From the Department of Biology and.,the Graduate Program in Genetics and Molecular Biology, Emory University, Atlanta, Georgia 30322
| | - Quidong Deng
- the Department of Biochemistry, Center for Neurodegenerative Diseases and
| | | | - Grace K Pavlath
- the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Katherine E Vest
- the Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267
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Vest KE, Phillips BL, Banerjee A, Apponi LH, Dammer EB, Xu W, Zheng D, Yu J, Tian B, Pavlath GK, Corbett AH. Novel mouse models of oculopharyngeal muscular dystrophy (OPMD) reveal early onset mitochondrial defects and suggest loss of PABPN1 may contribute to pathology. Hum Mol Genet 2017; 26:3235-3252. [PMID: 28575395 PMCID: PMC5886286 DOI: 10.1093/hmg/ddx206] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/14/2017] [Accepted: 05/23/2017] [Indexed: 01/09/2023] Open
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is a late onset disease caused by polyalanine expansion in the poly(A) binding protein nuclear 1 (PABPN1). Several mouse models have been generated to study OPMD; however, most of these models have employed transgenic overexpression of alanine-expanded PABPN1. These models do not recapitulate the OPMD patient genotype and PABPN1 overexpression could confound molecular phenotypes. We have developed a knock-in mouse model of OPMD (Pabpn1+/A17) that contains one alanine-expanded Pabpn1 allele under the control of the native promoter and one wild-type Pabpn1 allele. This mouse is the closest available genocopy of OPMD patients. We show that Pabpn1+/A17 mice have a mild myopathic phenotype in adult and aged animals. We examined early molecular and biochemical phenotypes associated with expressing native levels of A17-PABPN1 and detected shorter poly(A) tails, modest changes in poly(A) signal (PAS) usage, and evidence of mitochondrial damage in these mice. Recent studies have suggested that a loss of PABPN1 function could contribute to muscle pathology in OPMD. To investigate a loss of function model of pathology, we generated a heterozygous Pabpn1 knock-out mouse model (Pabpn1+/Δ). Like the Pabpn1+/A17 mice, Pabpn1+/Δ mice have mild histologic defects, shorter poly(A) tails, and evidence of mitochondrial damage. However, the phenotypes detected in Pabpn1+/Δ mice only partially overlap with those detected in Pabpn1+/A17 mice. These results suggest that loss of PABPN1 function could contribute to but may not completely explain the pathology detected in Pabpn1+/A17 mice.
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Affiliation(s)
- Katherine E. Vest
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Brittany L. Phillips
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Ayan Banerjee
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Luciano H. Apponi
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Eric B. Dammer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Weiting Xu
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Dinghai Zheng
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Julia Yu
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Bin Tian
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Grace K. Pavlath
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
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