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Brooks RL, Mistry CS, Dixon AM. Curvature sensing amphipathic helix in the C-terminus of RTNLB13 is conserved in all endoplasmic reticulum shaping reticulons in Arabidopsis thaliana. Sci Rep 2021; 11:6326. [PMID: 33737685 PMCID: PMC7973432 DOI: 10.1038/s41598-021-85866-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/05/2021] [Indexed: 11/24/2022] Open
Abstract
The reticulon family of integral membrane proteins are conserved across all eukaryotes and typically localize to the endoplasmic reticulum (ER), where they are involved in generating highly-curved tubules. We recently demonstrated that Reticulon-like protein B13 (RTNLB13) from Arabidopsis thaliana contains a curvature-responsive amphipathic helix (APH) important for the proteins' ability to induce curvature in the ER membrane, but incapable of generating curvature by itself. We suggested it acts as a feedback element, only folding/binding once a sufficient degree of curvature has been achieved, and stabilizes curvature without disrupting the bilayer. However, it remains unclear whether this is unique to RTNLB13 or is conserved across all reticulons-to date, experimental evidence has only been reported for two reticulons. Here we used biophysical methods to characterize a minimal library of putative APH peptides from across the 21 A. thaliana isoforms. We found that reticulons with the closest evolutionary relationship to RTNLB13 contain curvature-sensing APHs in the same location with sequence conservation. Our data reveal that a more distantly-related branch of reticulons developed a ~ 20-residue linker between the transmembrane domain and APH. This may facilitate functional flexibility as previous studies have linked these isoforms not only to ER remodeling but other cellular activities.
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Affiliation(s)
- Rhiannon L Brooks
- MAS Centre for Doctoral Training, University of Warwick, Coventry, CV4 7AL, UK
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Chandni S Mistry
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
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Ling J, Cai H, Lin M, Qi S, Du J, Chen L. RTN1-C mediates cerebral ischemia/reperfusion injury via modulating autophagy. Acta Biochim Biophys Sin (Shanghai) 2021; 53:170-178. [PMID: 33372676 DOI: 10.1093/abbs/gmaa162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Indexed: 11/12/2022] Open
Abstract
It has been widely accepted that autophagic cell death exacerbates the progression of cerebral ischemia/reperfusion (I/R). Our previous study revealed that overexpression of reticulon protein 1-C (RTN1-C) is involved in cerebral I/R injury. However, the underlying mechanisms have not been studied intensively. This study was designed to evaluate the effect of RTN1-C on autophagy under cerebral I/R. Using an in vitro oxygen-glucose deprivation followed by reoxygenation and a transient middle cerebral artery occlusion model in rats, we found that the expression of RTN1-C protein was significantly upregulated. We also revealed that RTN1-C knockdown suppressed overactivated autophagy both in vivo and in vitro, as indicated by decreased expressions of autophagic proteins. The number of Beclin-1/propidium iodide-positive cells was significantly less in the LV-shRTN1-C group than in the LV-shNC group. In addition, rapamycin, an activator of autophagy, aggravated cerebral I/R injury. RTN1-C knockdown reduced brain infarct volume, improved neurological deficits, and attenuated cell vulnerability to cerebral I/R injury after rapamycin treatment. Taken together, our findings demonstrated that the modulation of autophagy from RTN1-C may play vital roles in cerebral I/R injury, providing a potential therapeutic treatment for ischemic brain injury.
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Affiliation(s)
- Jun Ling
- Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230032, China
| | - Haijian Cai
- Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei 230022, China
- Anhui Provincial Key Laboratory of Microbiology & Parasitology, Anhui Medical University, Hefei 230032, China
| | - Muya Lin
- Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230032, China
| | - Shunli Qi
- Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230032, China
| | - Jian Du
- Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei 230022, China
- Anhui Provincial Key Laboratory of Microbiology & Parasitology, Anhui Medical University, Hefei 230032, China
| | - Lijian Chen
- Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230032, China
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Early defects in translation elongation factor 1α levels at excitatory synapses in α-synucleinopathy. Acta Neuropathol 2019; 138:971-986. [PMID: 31451907 DOI: 10.1007/s00401-019-02063-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/14/2019] [Accepted: 08/15/2019] [Indexed: 01/08/2023]
Abstract
Cognitive decline and dementia in neurodegenerative diseases are associated with synapse dysfunction and loss, which may precede neuron loss by several years. While misfolded and aggregated α-synuclein is recognized in the disease progression of synucleinopathies, the nature of glutamatergic synapse dysfunction and loss remains incompletely understood. Using fluorescence-activated synaptosome sorting (FASS), we enriched excitatory glutamatergic synaptosomes from mice overexpressing human alpha-synuclein (h-αS) and wild-type littermates to unprecedented purity. Subsequent label-free proteomic quantification revealed a set of proteins differentially expressed upon human alpha-synuclein overexpression. These include overrepresented proteins involved in the synaptic vesicle cycle, ER-Golgi trafficking, metabolism and cytoskeleton. Unexpectedly, we found and validated a steep reduction of eukaryotic translation elongation factor 1 alpha (eEF1A1) levels in excitatory synapses at early stages of h-αS mouse model pathology. While eEF1A1 reduction correlated with the loss of postsynapses, its immunoreactivity was found on both sides of excitatory synapses. Moreover, we observed a reduction in eEF1A1 immunoreactivity in the cingulate gyrus neuropil of patients with Lewy body disease along with a reduction in PSD95 levels. Altogether, our results suggest a link between structural impairments underlying cognitive decline in neurodegenerative disorders and local synaptic defects. eEF1A1 may therefore represent a limiting factor to synapse maintenance.
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Fan XX, Hao YY, Guo SW, Zhao XP, Xiang Y, Feng FX, Liang GT, Dong YW. Knockdown of RTN1-C attenuates traumatic neuronal injury through regulating intracellular Ca 2+ homeostasis. Neurochem Int 2018; 121:19-25. [PMID: 30352262 DOI: 10.1016/j.neuint.2018.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/28/2018] [Accepted: 10/18/2018] [Indexed: 11/24/2022]
Abstract
Reticulons (RTNs) are a family of membrane-bound proteins that are dominantly localized to the endoplasmic reticulum (ER) membrane. RTN1-C is one member of RTNs abundantly expressed in the brain and has been shown to mediate neuronal injury in cerebral ischemia models. In the present study, we investigated the role of RTN1-C in an in vitro brain trauma model mimicked by traumatic neuronal injury (TNI) in primary cultured cortical neurons. TNI increased the expression of RTN1-C in cortical neurons but had no effect on RTN1-A and RTN1-B. Knockdown of RTN1-C with specific siRNA (Si-RTN1-C) significantly decreased cytotoxicity and apoptosis after TNI. The results of Ca2+ imaging showed that intracellular Ca2+ overload induced by TNI was attenuated by RTN1-C knockdown. Furthermore, the activation of metabotropic glutamate receptor 1 (mGluR1)-induced Ca2+ response was partially prevented by Si-RTN1-C transfection. We also evaluated the role of RTN1-C in store-operated Ca2+ entry (SOCE) in cortical neurons using the ER Ca2+ inducer thapsigargin (Tg). The results showed that knockdown of RTN1-C alleviated the SOCE-mediated Ca2+ influx and decreased the expression of stromal interactive molecule 1 (STIM1). In summary, the present study found that knockdown of RTN1-C protected neurons against TNI via preservation of intracellular Ca2+ homeostasis, which was associated with the inhibition of mGluR1-mediated ER Ca2+ release and suppression of STIM1-related SOCE. Thus, RTN1-C might represent a therapeutic target for traumatic brain injury (TBI) research.
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Affiliation(s)
- Xiao-Xuan Fan
- Neurosurgery Department, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China; Neurosurgery Department, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, Shaanxi, China
| | - Yu-Ying Hao
- Neurosurgery Department, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, Shaanxi, China
| | - Shi-Wen Guo
- Neurosurgery Department, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China.
| | - Xiao-Ping Zhao
- Neurosurgery Department, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, Shaanxi, China
| | - Yi Xiang
- Neurosurgery Department, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China
| | - Fei-Xue Feng
- Medical Inspection Center, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, Shaanxi, China
| | - Ge-Ting Liang
- Neurosurgery Department, Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, 712000, Shaanxi, China
| | - Yu-Wei Dong
- Neurosurgery Department, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China
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Dornadula S, Thiruppathi S, Palanisamy R, Umapathy D, Suzuki T, K. Mohanram R. Differential proteomic profiling identifies novel molecular targets of pterostilbene against experimental diabetes. J Cell Physiol 2018; 234:1996-2012. [DOI: 10.1002/jcp.26835] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/10/2018] [Indexed: 02/03/2023]
Affiliation(s)
- Sireesh Dornadula
- SRM Research InstituteSRM Institute of Science and TechnologyKattankulathur Tamil Nadu India
- Department of BiotechnologySchool of Bioengineering, SRM Institute of Science and TechnologyKattankulathur Tamil Nadu India
| | - Suresh Thiruppathi
- Division of Cellular and Gene Therapy ProductsNational Institute of Health SciencesTokyo Japan
| | | | - Dhamodharan Umapathy
- SRM Research InstituteSRM Institute of Science and TechnologyKattankulathur Tamil Nadu India
| | - Takayoshi Suzuki
- Division of Cellular and Gene Therapy ProductsNational Institute of Health SciencesTokyo Japan
| | - Ramkumar K. Mohanram
- SRM Research InstituteSRM Institute of Science and TechnologyKattankulathur Tamil Nadu India
- Department of BiotechnologySchool of Bioengineering, SRM Institute of Science and TechnologyKattankulathur Tamil Nadu India
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RTN1-C mediates cerebral ischemia/reperfusion injury via ER stress and mitochondria-associated apoptosis pathways. Cell Death Dis 2017; 8:e3080. [PMID: 28981095 PMCID: PMC5680587 DOI: 10.1038/cddis.2017.465] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/27/2017] [Accepted: 08/17/2017] [Indexed: 01/15/2023]
Abstract
The reticulon family has been found to induce apoptosis, inhibit axon regeneration and regulate protein trafficking. However, little is known about the mechanisms of how reticulon proteins are involved in neuronal death-promoting processes during ischemia. Here, we report that the expression of Reticulon Protein 1-C (RTN1-C) was associated with the progression of cerebral ischemia/reperfusion (I/R) injury. Using a combination of rat middle cerebral artery occlusion (MCAO) stroke and oxygen-glucose deprivation followed by reoxygenation (OGD/R) models, we determined that the expression of RTN1-C was significantly increased during cerebral ischemic/reperfusion. RTN1-C overexpression induced apoptosis and increased the cell vulnerability to ischemic injury, whereas RTN1-C knockdown reversed ischemia-induced apoptosis and attenuated the vulnerability of OGD/R-treated neural cells. Mechanistically, we demonstrated that RTN1-C mediated OGD/R-induced apoptosis through ER stress and mitochondria-associated pathways. RTN1-C interacted with Bcl-xL and increased its localization in the ER, thus reducing the anti-apoptotic activity of Bcl-xL. Most importantly, knockdown of Rtn1-c expression in vivo attenuated apoptosis in MCAO rats and reduced the extent of I/R-induced brain injury, as assessed by infarct volume and neurological score. Collectively, these data support for the first time that RTN1-C may represent a novel candidate for therapies against cerebral ischemia/reperfusion injury.
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Abstract
Three neurodegenerative diseases [Amyotrophic Lateral Sclerosis (ALS), Parkinson's disease (PD) and Alzheimer's disease (AD)] have many characteristics like pathological mechanisms and genes. In this sense some researchers postulate that these diseases share the same alterations and that one alteration in a specific protein triggers one of these diseases. Analyses of gene expression may shed more light on how to discover pathways, pathologic mechanisms associated with the disease, biomarkers and potential therapeutic targets. In this review, we analyze four microarrays related to three neurodegenerative diseases. We will systematically examine seven genes (CHN1, MDH1, PCP4, RTN1, SLC14A1, SNAP25 and VSNL1) that are altered in the three neurodegenerative diseases. A network was built and used to identify pathways, miRNA and drugs associated with ALS, AD and PD using Cytoscape software an interaction network based on the protein interactions of these genes. The most important affected pathway is PI3K-Akt signalling. Thirteen microRNAs (miRNA-19B1, miRNA-107, miRNA-124-1, miRNA-124-2, miRNA-9-2, miRNA-29A, miRNA-9-3, miRNA-328, miRNA-19B2, miRNA-29B2, miRNA-124-3, miRNA-15A and miRNA-9-1) and four drugs (Estradiol, Acetaminophen, Resveratrol and Progesterone) for new possible treatments were identified.
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Affiliation(s)
| | - Marcelo Alarcón
- Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Universidad de Talca, Talca 3460000, Chile; Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), Universidad de Talca, Talca 3460000, Chile.
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Chen L, Wan L, Du J, Shen Y. Identification of MANF as a protein interacting with RTN1-C. Acta Biochim Biophys Sin (Shanghai) 2015; 47:91-7. [PMID: 25543119 DOI: 10.1093/abbs/gmu125] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Reticulons (RTNs) constitute a family of endoplasmic reticulum (ER)-associated proteins with a reticular distribution. Recently, evidence has shown that they exert a cancer-specific proapoptotic function via interaction or modulation of specific proteins. Such evidence is particularly associated with the RTN1-C family members. In order to explore proteins that interact with RTN1-C, the yeast two-hybrid system and regular molecular biological techniques were used to screen the human fetal brain cDNA library. As a result, seven RTN1-C interacting proteins including Homo sapiens mesencephalic astrocyte-derived neurotrophic factor (MANF) were obtained. The interactions between RTN1-C and its interacting proteins were confirmed by β-galactosidase assay and growth test in selective media. Moreover, the MANF/RTN1-C interaction was verified in vitro by glutathione S-transferase pull-down assay and in vivo by immunoprecipitation assay. By immunofluorescence assay, it was found that MANF co-localized with RTN1-C in the ER. Knockdown of RTN1-C reduced the localization of MANF in the ER. These results provide clues to further explore the function of RTN1-C and MANF in neurodegenerative diseases and cancer.
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Affiliation(s)
- Lijian Chen
- School of Pharmacy, Anhui Medical University, Hefei 230032, China Department of Anaesthesiology of the First Affiliated Hospital, Anhui Medical University, Hefei 230032, China
| | - Lijuan Wan
- School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Jian Du
- School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Yuxian Shen
- School of Pharmacy, Anhui Medical University, Hefei 230032, China School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
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