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Sasaki O, Yano-Nashimoto S, Yamaguchi S. A proton channel, Otopetrin 1 (OTOP1) is N-glycosylated at two asparagine residues in third extracellular loop. J Cell Physiol 2024:e31403. [PMID: 39129225 DOI: 10.1002/jcp.31403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 07/18/2024] [Accepted: 07/30/2024] [Indexed: 08/13/2024]
Abstract
A proton (H+) channel, Otopetrin 1 (OTOP1) is an acid sensor in the sour taste receptor cells. Although OTOP1 is known to be activated by extracellular acid, no posttranslational modification of OTOP1 has been reported. As one of the posttranslational modifications, glycosylation is known to modulate many ion channels. In this study, we investigated whether OTOP1 is glycosylated and how the glycosylation affects OTOP1 function. Pharmacological and enzymatic examinations (using an N-glycosylation inhibitor, tunicamycin and peptide: N-glycanase F [PNGase F]) revealed that overexpressed mouse OTOP1 was N-glycosylated. As the N-glycans were Endoglycosidase H (Endo H)-sensitive, they were most likely high-mannose type. A site-directed mutagenesis approach revealed that both two asparagine residues (N238 and N251) in the third extracellular loop between the fifth transmembrane region and the sixth transmembrane region (L5-6) were the glycosylation sites. Prevention of the glycosylations by the mutations of the asparagine residues or by tunicamycin treatment diminished the whole-cell OTOP1 current densities. The results of cell surface biotinylation assay showed that the prevention of the glycosylations reduced the surface expression of OTOP1 at the plasma membrane. These results indicate that mouse OTOP1 is N-glycosylated at N238 and N251, and that the glycosylations are necessary for OTOP1 to show the maximum degree of H+ current densities at the plasma membrane through promoting its targeting to the plasma membrane. These findings on glycosylations of OTOP1 will be a part of a comprehensive understanding on the regulations of OTOP1 function.
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Affiliation(s)
- Omi Sasaki
- Laboratory of Physiology, Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Saori Yano-Nashimoto
- Laboratory of Physiology, Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Soichiro Yamaguchi
- Laboratory of Physiology, Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
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Abad-Rodríguez J, Brocca ME, Higuero AM. Glycans and Carbohydrate-Binding/Transforming Proteins in Axon Physiology. ADVANCES IN NEUROBIOLOGY 2023; 29:185-217. [PMID: 36255676 DOI: 10.1007/978-3-031-12390-0_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The mature nervous system relies on the polarized morphology of neurons for a directed flow of information. These highly polarized cells use their somatodendritic domain to receive and integrate input signals while the axon is responsible for the propagation and transmission of the output signal. However, the axon must perform different functions throughout development before being fully functional for the transmission of information in the form of electrical signals. During the development of the nervous system, axons perform environmental sensing functions, which allow them to navigate through other regions until a final target is reached. Some axons must also establish a regulated contact with other cells before reaching maturity, such as with myelinating glial cells in the case of myelinated axons. Mature axons must then acquire the structural and functional characteristics that allow them to perform their role as part of the information processing and transmitting unit that is the neuron. Finally, in the event of an injury to the nervous system, damaged axons must try to reacquire some of their immature characteristics in a regeneration attempt, which is mostly successful in the PNS but fails in the CNS. Throughout all these steps, glycans perform functions of the outermost importance. Glycans expressed by the axon, as well as by their surrounding environment and contacting cells, encode key information, which is fine-tuned by glycan modifying enzymes and decoded by glycan binding proteins so that the development, guidance, myelination, and electrical transmission functions can be reliably performed. In this chapter, we will provide illustrative examples of how glycans and their binding/transforming proteins code and decode instructive information necessary for fundamental processes in axon physiology.
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Affiliation(s)
- José Abad-Rodríguez
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain.
| | - María Elvira Brocca
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
| | - Alonso Miguel Higuero
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
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Filatova TS, Abramochkin DV, Pavlova NS, Pustovit KB, Konovalova OP, Kuzmin VS, Dobrzynski H. Repolarizing potassium currents in working myocardium of Japanese quail: a novel translational model for cardiac electrophysiology. Comp Biochem Physiol A Mol Integr Physiol 2021; 255:110919. [DOI: 10.1016/j.cbpa.2021.110919] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/06/2021] [Accepted: 02/06/2021] [Indexed: 12/14/2022]
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Bomkamp C, Tripathy SJ, Bengtsson Gonzales C, Hjerling-Leffler J, Craig AM, Pavlidis P. Transcriptomic correlates of electrophysiological and morphological diversity within and across excitatory and inhibitory neuron classes. PLoS Comput Biol 2019; 15:e1007113. [PMID: 31211786 PMCID: PMC6599125 DOI: 10.1371/journal.pcbi.1007113] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/28/2019] [Accepted: 05/18/2019] [Indexed: 12/31/2022] Open
Abstract
In order to further our understanding of how gene expression contributes to key functional properties of neurons, we combined publicly accessible gene expression, electrophysiology, and morphology measurements to identify cross-cell type correlations between these data modalities. Building on our previous work using a similar approach, we distinguished between correlations which were "class-driven," meaning those that could be explained by differences between excitatory and inhibitory cell classes, and those that reflected graded phenotypic differences within classes. Taking cell class identity into account increased the degree to which our results replicated in an independent dataset as well as their correspondence with known modes of ion channel function based on the literature. We also found a smaller set of genes whose relationships to electrophysiological or morphological properties appear to be specific to either excitatory or inhibitory cell types. Next, using data from PatchSeq experiments, allowing simultaneous single-cell characterization of gene expression and electrophysiology, we found that some of the gene-property correlations observed across cell types were further predictive of within-cell type heterogeneity. In summary, we have identified a number of relationships between gene expression, electrophysiology, and morphology that provide testable hypotheses for future studies.
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Affiliation(s)
- Claire Bomkamp
- Department of Psychiatry, University of British Columbia, Vancouver BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver BC, Canada
| | - Shreejoy J. Tripathy
- Department of Psychiatry, University of British Columbia, Vancouver BC, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver BC, Canada
| | - Carolina Bengtsson Gonzales
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jens Hjerling-Leffler
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Ann Marie Craig
- Department of Psychiatry, University of British Columbia, Vancouver BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver BC, Canada
| | - Paul Pavlidis
- Department of Psychiatry, University of British Columbia, Vancouver BC, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver BC, Canada
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Zhang X, Shang J, Wang X, Cheng G, Jiang Y, Liu D, Xiao J, Zhao Z. Microarray analysis reveals long non‑coding RNA SOX2OT as a novel candidate regulator in diabetic nephropathy. Mol Med Rep 2018; 18:5058-5068. [PMID: 30320339 PMCID: PMC6236268 DOI: 10.3892/mmr.2018.9534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/14/2018] [Indexed: 01/24/2023] Open
Abstract
Diabetic nephropathy (DN) is a highly complex syndrome involving multiple dysregulated biological processes. Long non-coding RNAs (lncRNAs) are now believed to have an important function in various diseases. However, their roles in DN remain largely unknown. Therefore, the present study was performed in order to investigate the lncRNAs that have a crucial role in DN. db/db mice were used as a DN model while db/m mice served as a control to search for lncRNAs which may have important roles in DN. Microarray and bioinformatics analysis gave an overview of the features of differentially expressed genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis demonstrated the typical biological alterations in DN. A co-expression network of lncRNAs and mRNAs revealed the complex interaction pattern in DN conditions. Further data investigation indicated that SOX2-overlapping transcript (SOX2OT), which was significantly downregulated in DN mice, may be the potentially functional lncRNA contributing to the onset of DN. The UCSC database demonstrated that SOX2OT was highly conserved in mice and humans. Additionally further study using cultured human podocytes and mesangial cells confirmed the downregulation of SOX2OT using reverse transcription-quantitative polymerase chain reaction and fluorescence in situ hybridization. However, the cellular location of SOX2OT depended on certain cell types. Taken together, the results of the present study indicated that SOX2OT may act as an important regulator in the pathogenesis of DN by interacting with various mRNAs with critical roles in DN.
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Affiliation(s)
- Xiaoxue Zhang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Jin Shang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Xiaoyang Wang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Genyang Cheng
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Yumin Jiang
- Department of Emergency, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Dong Liu
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Jing Xiao
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Zhanzheng Zhao
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Colley CS, England E, Linley JE, Wilkinson TCI. Screening Strategies for the Discovery of Ion Channel Monoclonal Antibodies. ACTA ACUST UNITED AC 2018; 82:e44. [DOI: 10.1002/cpph.44] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Caroline S. Colley
- Antibody Discovery and Protein Engineering, MedImmune; Cambridge United Kingdom
| | - Elizabeth England
- Antibody Discovery and Protein Engineering, MedImmune; Cambridge United Kingdom
| | - John E. Linley
- Neuroscience, IMED Biotech Unit, AstraZeneca; Cambridge United Kingdom
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Hall MK, Weidner DA, Dayal S, Pak E, Murashov AK, Schwalbe RA. Membrane Distribution and Activity of a Neuronal Voltage-Gated K+ Channel is Modified by Replacement of Complex Type N-Glycans with Hybrid Type. ACTA ACUST UNITED AC 2017; 6. [PMID: 30271698 PMCID: PMC6157612 DOI: 10.4172/2168-958x.1000128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abnormal modifications in N-glycosylation processing are commonly associated with neurological disorders, although the impact of specific N-glycans on neuronal excitability is unknown. By replacement of complex types of N-glycans with hybrid types in neuroblastoma cells, we provide the first study that addresses how distinct N-glycan types impact neuronal excitability. Using CRISPR/Cas9 technology, NB_1, a clonal cell line derived from rat neuroblastoma cells (NB), was modified to create an N-glycosylation mutant cell line, NB_1 (-Mgat2), which expresses predominantly hybrid type N-glycans. Western and lectin blotting, flow cytometry, TIRF and DIC microscopy, and patch clamp studies were conducted. Lectin binding revealed the predominant type of N-glycans expressed in NB_1 (-Mgat2) is hybrid while those of NB and NB_1 are complex. Kv3.1 b-expressing cells with complex N-glycans localized more glycosylated Kv3.1b to the neurites than cells with hybrid N-glycans. Further the absence of N-glycan attachment to Kv3.1b was critical for sub-plasma distribution of Kv3.1b to neurites in primary adult mammalian neurons, along with NB cells. Replacement of complex type N-glycans with hybrid type hindered the opening and closing rates of outward ionic currents of Kv3.1 b-expressing NB cells. The lacks of N-glycan attachment hindered the rates even more but were not significantly different between the NB cell lines. Taken together, our evidence supports N-glycosylation impacts the sub-plasma membrane localization and activity of Kv3.1 b-containing channels. We propose that N-glycosylation processing of Kv3.1 b-containing channels contributes to neuronal excitability, and abnormal modifications in N-glycosylation processing of Kv3.1b could contribute to neurological diseases.
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Affiliation(s)
- M Kristen Hall
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, USA
| | - Douglas A Weidner
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, USA
| | - Sahil Dayal
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, USA
| | - Elena Pak
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, USA
| | - Alexander K Murashov
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, USA
| | - Ruth A Schwalbe
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, USA
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