1
|
Li S, Al-Sheikh U, Chen Y, Kang L. Nematode homologs of the sour taste receptor Otopetrin1 are evolutionarily conserved acid-sensitive proton channels. Front Cell Dev Biol 2023; 11:1133890. [PMID: 36776560 PMCID: PMC9909269 DOI: 10.3389/fcell.2023.1133890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Numerous taste receptors and related molecules have been identified in vertebrates and invertebrates. Otopetrin1 has recently been identified as mammalian sour taste receptor which is essential for acid sensation. However, whether other Otopetrin proteins are involved in PH-sensing remains unknown. In C. elegans, there are eight otopetrin homologous genes but their expression patterns and functions have not been reported so far. Through heterologous expression in HEK293T cells, we found that ceOTOP1a can be activated by acid in NMDG+ solution without conventional cations, which generated inward currents and can be blocked by zinc ions. Moreover, we found that Otopetrin channels are widely expressed in numerous tissues, especially in sensory neurons in the nematode. These results suggest that the biophysical characteristics of the Otopetrin channels in nematodes are generally conserved. However, a series of single gene mutations of otopetrins, which were constructed by CRISPR-Cas9 method, did not affect either calcium responses in ASH polymodal sensory neurons to acid stimulation or acid avoidance behaviors, suggesting that Otopetrin channels might have diverse functions among species. This study reveals that nematode Otopetrins are evolutionarily conserved acid-sensitive proton channels, and provides a framework for further revealing the function and mechanisms of Otopetrin channels in both invertebrates and vertebrates.
Collapse
Affiliation(s)
- Shitian Li
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Umar Al-Sheikh
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yili Chen
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,*Correspondence: Yili Chen, ; Lijun Kang,
| | - Lijun Kang
- Department of Neurobiology and Department of Neurosurgery of the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China,Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China,NHC and CAMS Key Laboratory of Medical Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China,*Correspondence: Yili Chen, ; Lijun Kang,
| |
Collapse
|
2
|
Nisar A, Kayani MA, Nasir W, Mehmood A, Ahmed MW, Parvez A, Mahjabeen I. Fyn and Lyn gene polymorphisms impact the risk of thyroid cancer. Mol Genet Genomics 2022; 297:1649-1659. [PMID: 36058999 DOI: 10.1007/s00438-022-01946-7] [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: 06/27/2021] [Accepted: 08/11/2022] [Indexed: 10/14/2022]
Abstract
Thyroid cancer is the most common malignancy of the endocrine glands, and during last couple of decades, its incidence has risen alarmingly, across the globe. Etiology of thyroid cancer is still debatable. There are a few worth mentioning risk factors which contribute to initiation of abnormalities in thyroid gland leading to cancer. Genetic instability is major risk factors in thyroid carcinogenesis. Among the genetic factors, the Src family of genes (Src, Yes1, Fyn and Lyn) have been implicated in many cancers but there is little data regarding the association of these (Src, Yes1, Fyn and Lyn) genes with thyroid carcinogenesis. Fyn and Lyn genes of Src family found engaged in proliferation, migration, invasion, angiogenesis, and metastasis in different cancers. This study was planned to examine the effect of Fyn and Lyn SNPs on thyroid cancer risk in Pakistani population in 500 patients and 500 controls. Three polymorphisms of Fyn gene (rs6916861, rs2182644 and rs12910) and three polymorphisms of Lyn gene (rs2668011, rs45587541 and rs45489500) were analyzed using Tetra-primer ARMS-PCR followed by DNA sequencing. SNP rs6916861 of Fyn gene mutant genotype (CC) showed statistically significant threefold increased risk of thyroid cancer (P < 0.0001). In case of rs2182644 of Fyn gene, mutant genotype (AA) indicated statistically significant 17-fold increased risk of thyroid cancer (P < 0.0001). Statistically significant threefold increased risk of thyroid cancer was observed in genotype AC (P < 0.0001) of Fyn gene polymorphism rs12910. In SNP rs2668011 of Lyn gene, TT genotype showed statistically significant threefold increased risk of thyroid cancer (P < 0.0001). In case of rs45587541 of Lyn gene, GA genotypes showed statistically significant 11-fold increased risk in thyroid cancer (P < 0.0001). Haplotype analysis revealed that AAATAG*, AGACAG*, AGCCAA*, AGCCAG*, CAATAG*, CGCCAG* and CGCCGA* haplotypes of Fyn and Lyn polymorphisms are associated with increased thyroid cancer risk. These results showed that genotypes and allele distribution of Fyn and Lyn are significantly linked with increased thyroid cancer risk and could be genetic adjuster for said disease.
Collapse
Affiliation(s)
- Asif Nisar
- Cancer Genetics and Epigenetics Lab, Department of Biosciences, COMSATS University Islamabad, Park Road Tarlai Kalan, Islamabad, Pakistan
| | - Mahmood Akhtar Kayani
- Cancer Genetics and Epigenetics Lab, Department of Biosciences, COMSATS University Islamabad, Park Road Tarlai Kalan, Islamabad, Pakistan
| | - Wajiha Nasir
- Department of Radiation, Nuclear Oncology Radiation Institute, Islamabad, Pakistan
| | - Azhar Mehmood
- Cancer Genetics and Epigenetics Lab, Department of Biosciences, COMSATS University Islamabad, Park Road Tarlai Kalan, Islamabad, Pakistan
| | - Malik Waqar Ahmed
- Cancer Genetics and Epigenetics Lab, Department of Biosciences, COMSATS University Islamabad, Park Road Tarlai Kalan, Islamabad, Pakistan.,Pakistan Institute of Rehabilitation Sciences (PIRS), Isra University Islamabad Campus, Islamabad, Pakistan
| | - Aamir Parvez
- Cancer Genetics and Epigenetics Lab, Department of Biosciences, COMSATS University Islamabad, Park Road Tarlai Kalan, Islamabad, Pakistan
| | - Ishrat Mahjabeen
- Cancer Genetics and Epigenetics Lab, Department of Biosciences, COMSATS University Islamabad, Park Road Tarlai Kalan, Islamabad, Pakistan.
| |
Collapse
|
3
|
Abstract
Sour taste, the taste of acids, is one of the most enigmatic of the five basic taste qualities; its function is unclear and its receptor was until recently unknown. Sour tastes are transduced in taste buds on the tongue and palate epithelium by a subset of taste receptor cells, known as type III cells. Type III cells express a number of unique markers, including the PKD2L1 gene, which allow for their identification and manipulation. These cells respond to acid stimuli with action potentials and release neurotransmitters onto afferent nerve fibers, with cell bodies in geniculate and petrosal ganglia. Here, we review classical studies of sour taste leading up to the identification of the sour receptor as the proton channel, OTOP1. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Heather N Turner
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, California, USA; ,
| | - Emily R Liman
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, California, USA; ,
| |
Collapse
|
4
|
Mackowetzky K, Yoon KH, Mackowetzky EJ, Waskiewicz AJ. Development and evolution of the vestibular apparatuses of the inner ear. J Anat 2021; 239:801-828. [PMID: 34047378 PMCID: PMC8450482 DOI: 10.1111/joa.13459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/07/2021] [Accepted: 05/06/2021] [Indexed: 12/16/2022] Open
Abstract
The vertebrate inner ear is a labyrinthine sensory organ responsible for perceiving sound and body motion. While a great deal of research has been invested in understanding the auditory system, a growing body of work has begun to delineate the complex developmental program behind the apparatuses of the inner ear involved with vestibular function. These animal studies have helped identify genes involved in inner ear development and model syndromes known to include vestibular dysfunction, paving the way for generating treatments for people suffering from these disorders. This review will provide an overview of known inner ear anatomy and function and summarize the exciting discoveries behind inner ear development and the evolution of its vestibular apparatuses.
Collapse
Affiliation(s)
- Kacey Mackowetzky
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | - Kevin H. Yoon
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
| | | | - Andrew J. Waskiewicz
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
- Women & Children’s Health Research InstituteUniversity of AlbertaEdmontonAlbertaCanada
| |
Collapse
|
5
|
Zhang S, Xing J, Gong Y, Li P, Wang B, Xu L. Downregulation of VDR in benign paroxysmal positional vertigo patients inhibits otolith‑associated protein expression levels. Mol Med Rep 2021; 24:591. [PMID: 34165161 DOI: 10.3892/mmr.2021.12230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 11/04/2020] [Indexed: 11/06/2022] Open
Abstract
Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vertigo‑associated disease. Vitamin D (VD) helps maintain normal otolith function and may be associated with BPPV. VD exerts its biological functions primarily via the VD receptor (VDR). The present study demonstrated that serum VD levels were significantly decreased in patients with BPPV compared with in controls. VDR, otolith‑associated protein otoconin‑90 (OC90) and NADPH oxidase 3 (NOX3) expression levels were also significantly decreased in patients with BPPV compared with in controls. Furthermore, a positive correlation was observed between VD levels and VDR expression. Receiver operating characteristic curve analysis identified VDR expression levels as a potential diagnostic marker for BPPV. OC90 and NOX3 expression levels were notably lower in the inner ear tissue of VDR knockout mice compared with in those of wild‑type mice. In mice overexpressing VDR, OC90 and NOX3 were also overexpressed. Following intravenous injection of VD in VDR knockout mice, expression levels of OC90 and NOX3 were not significantly different from those in VDR knockout mice injected with saline. This indicated that VDR may be underexpressed in patients with BPPV and was associated with the expression levels of otolith‑associated proteins. Moreover, VDR mediated VD activation, leading to otolith protein formation. The present study provided a novel theoretical basis for BPPV onset that may facilitate the development of more effective diagnostic and treatment options.
Collapse
Affiliation(s)
- Shu Zhang
- Department of Otolaryngology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia 010110, P.R. China
| | - Juanli Xing
- Department of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710048, P.R. China
| | - Yulin Gong
- Department of Rheumatic Immunology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia 010110, P.R. China
| | - Ping Li
- Department of Obstetrics, Yongkang Maternal and Child Health Care Hospital, Yongkang, Zhejiang 321300, P.R. China
| | - Boqian Wang
- Department of Otolaryngology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia 010110, P.R. China
| | - Ling Xu
- Department of Otolaryngology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia 010110, P.R. China
| |
Collapse
|
6
|
Abstract
Sour taste, which is evoked by low pH, is one of the original four fundamental taste qualities, recognized as a distinct taste sensation for centuries, and universally aversive across diverse species. It is generally assumed to have evolved for detection of acids in unripe fruit and spoiled food. But despite decades of study, only recently have the receptor, the neurotransmitter, and the circuits for sour taste been identified. In this review, we describe studies leading up to the identification of the sour receptor as OTOP1, an ion channel that is selectively permeable to protons. We also describe advances in our understanding of how information is transmitted from the taste receptor cells to gustatory neurons, leading to behavioral aversion to acids.
Collapse
Affiliation(s)
- Emily R Liman
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, 3641 Watt Way, Los Angeles, CA 90089, USA
| | - Sue C Kinnamon
- Department of Otolaryngology and Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, 12700 E 19(th) Avenue, Aurora, CO 80045, USA
| |
Collapse
|
7
|
Zhang J, Jin H, Zhang W, Ding C, O'Keeffe S, Ye M, Zuker CS. Sour Sensing from the Tongue to the Brain. Cell 2019; 179:392-402.e15. [PMID: 31543264 DOI: 10.1016/j.cell.2019.08.031] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/04/2019] [Accepted: 08/15/2019] [Indexed: 12/19/2022]
Abstract
The ability to sense sour provides an important sensory signal to prevent the ingestion of unripe, spoiled, or fermented foods. Taste and somatosensory receptors in the oral cavity trigger aversive behaviors in response to acid stimuli. Here, we show that the ion channel Otopetrin-1, a proton-selective channel normally involved in the sensation of gravity in the vestibular system, is essential for sour sensing in the taste system. We demonstrate that knockout of Otop1 eliminates acid responses from sour-sensing taste receptor cells (TRCs). In addition, we show that mice engineered to express otopetrin-1 in sweet TRCs have sweet cells that also respond to sour stimuli. Next, we genetically identified the taste ganglion neurons mediating each of the five basic taste qualities and demonstrate that sour taste uses its own dedicated labeled line from TRCs in the tongue to finely tuned taste neurons in the brain to trigger aversive behaviors.
Collapse
Affiliation(s)
- Jin Zhang
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Hao Jin
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Wenyi Zhang
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Cheng Ding
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Sean O'Keeffe
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Mingyu Ye
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Charles S Zuker
- Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10032, USA; Mortimer B. Zukerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA.
| |
Collapse
|
8
|
Cellular and Neural Responses to Sour Stimuli Require the Proton Channel Otop1. Curr Biol 2019; 29:3647-3656.e5. [PMID: 31543453 DOI: 10.1016/j.cub.2019.08.077] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/08/2019] [Accepted: 08/30/2019] [Indexed: 11/24/2022]
Abstract
The sense of taste allows animals to sample chemicals in the environment prior to ingestion. Of the five basic tastes, sour, the taste of acids, had remained among the most mysterious. Acids are detected by type III taste receptor cells (TRCs), located in taste buds across the tongue and palate epithelium. The first step in sour taste transduction is believed to be entry of protons into the cell cytosol, which leads to cytosolic acidification and the generation of action potentials. The proton-selective ion channel Otop1 is expressed in type III TRCs and is a candidate sour receptor. Here, we tested the contribution of Otop1 to taste cell and gustatory nerve responses to acids in mice in which Otop1 was genetically inactivated (Otop1-KO mice). We first show that Otop1 is required for the inward proton current in type III TRCs from different parts of the tongue that are otherwise molecularly heterogeneous. We next show that in type III TRCs from Otop1-KO mice, intracellular pH does not track with extracellular pH and that moderately acidic stimuli do not elicit trains of action potentials, as they do in type III TRCs from wild-type mice. Moreover, gustatory nerve responses in Otop1-KO mice were severely and selectively attenuated for acidic stimuli, including citric acid and HCl. These results establish that the Otop1 proton channel plays a critical role in acid detection in the mouse gustatory system, evidence that it is a bona fide sour taste receptor.
Collapse
|
9
|
Lopez IA, Ishiyama G, Acuna D, Ishiyama A. Otopetrin-2 Immunolocalization in the Human Macula Utricle. Ann Otol Rhinol Laryngol 2019; 128:96S-102S. [PMID: 31092032 PMCID: PMC6767922 DOI: 10.1177/0003489419834952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND In the present study, we investigated the localization of otopetrin-2-a member of the otopetrin family that encodes proton-selective ion channels-in the human macula utricle using immunohistochemistry. METHODS Macula utricle were acquired at surgery from patients who required transmastoid labyrinthectomy for intractable vertigo due to Meniere's disease (MD; n = 3) and/or vestibular drops attacks (VDA; n = 2) and from temporal bones (n = 2) acquired at autopsy from individuals with no balance disorders. Immunofluorescence staining with otopetrin-2 (rabbit affinity purified polyclonal antibody) and GFAP (mouse monoclonal antibody) to identify vestibular supporting cells was made in formalin fixed cryostat sections or whole microdissected utricle (for flat mount preparations). Secondary antibodies against rabbit and mouse were used for the identification of both proteins. Digital fluorescent images were obtained using a high-resolution laser confocal microscope. RESULTS Using cryostat sections and flat mount preparations otopetrin-2 immunofluorescence was seen as punctated signal throughout the supporting cells cytoplasm. GFAP immunofluorescence was present in the supporting cell cytoplasm. The distribution of otopetrin-2 was similar in the macula utricle obtained from MD, VDA, or autopsy normative patients. CONCLUSIONS Otopetrin-2 was localized in supporting cells in a similar fashion that otopetrin-1 previously reported in the mouse macula utricle. The differential expression of otopetrin-2 in the supporting cells of the human macula utricle suggest an important role in the vestibular sensory periphery homeostasis and otolith maintenance.
Collapse
Affiliation(s)
- Ivan A. Lopez
- Department of Head & Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gail Ishiyama
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Dora Acuna
- Department of Head & Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Akira Ishiyama
- Department of Head & Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| |
Collapse
|
10
|
Holman HA, Poppi LA, Frerck M, Rabbitt RD. Spontaneous and Acetylcholine Evoked Calcium Transients in the Developing Mouse Utricle. Front Cell Neurosci 2019; 13:186. [PMID: 31133810 PMCID: PMC6514437 DOI: 10.3389/fncel.2019.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Spontaneous calcium transients are present during early postnatal development in the mouse retina and cochlea, and play an important role in maturation of the sensory organs and neural circuits in the central nervous system (CNS). It is not known whether similar calcium transients occur during postnatal development in the vestibular sensory organs. Here we demonstrate spontaneous intracellular calcium transients in sensory hair cells (HCs) and supporting cells (SCs) in the murine utricular macula during the first two postnatal weeks. Calcium transients were monitored using a genetically encoded calcium indicator, GCaMP5G (G5), at 100 ms-frame−1 in excised utricle sensory epithelia, including HCs, SCs, and neurons. The reporter line expressed G5 and tdTomato (tdT) in a Gad2-Cre dependent manner within a subset of utricular HCs, SCs and neurons. Kinetics of the G5 reporter limited temporal resolution to calcium events lasting longer than 200 ms. Spontaneous calcium transients lasting 1-2 s were observed in the expressing population of HCs at birth and slower spontaneous transients lasting 10-30 s appeared in SCs by P3. Beginning at P5, calcium transients could be modulated by application of the efferent neurotransmitter acetylcholine (ACh). In mature mice, calcium transients in the utricular macula occurred spontaneously, had a duration 1-2 s, and could be modulated by the exogenous application of acetylcholine (ACh) or muscarine. Long-lasting calcium transients evoked by ACh in mature mice were blocked by atropine, consistent with previous reports describing the role of muscarinic receptors expressed in calyx bearing afferents in efferent control of vestibular sensation. Large spontaneous and ACh evoked transients were reversibly blocked by the inositol trisphosphate receptor (IP3R) antagonist aminoethoxydiphenyl borate (2-APB). Results demonstrate long-lasting calcium transients are present in the utricular macula during the first postnatal week, and that responses to ACh mature over this same time period.
Collapse
Affiliation(s)
- Holly A Holman
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Lauren A Poppi
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,School of Biomedical Science and Pharmacy, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia
| | - Micah Frerck
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Richard D Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States.,Neuroscience Program, University of Utah, Salt Lake City, UT, United States.,Otolaryngology-Head and Neck Surgery, University of Utah, Salt Lake City, UT, United States
| |
Collapse
|
11
|
Abstract
Ramsey and DeSimone highlight the recent discovery of a new family of proton channels.
Collapse
Affiliation(s)
- I Scott Ramsey
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA
| | - John A DeSimone
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA
| |
Collapse
|
12
|
Tu YH, Cooper AJ, Teng B, Chang RB, Artiga DJ, Turner HN, Mulhall EM, Ye W, Smith AD, Liman ER. An evolutionarily conserved gene family encodes proton-selective ion channels. Science 2018; 359:1047-1050. [PMID: 29371428 DOI: 10.1126/science.aao3264] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022]
Abstract
Ion channels form the basis for cellular electrical signaling. Despite the scores of genetically identified ion channels selective for other monatomic ions, only one type of proton-selective ion channel has been found in eukaryotic cells. By comparative transcriptome analysis of mouse taste receptor cells, we identified Otopetrin1 (OTOP1), a protein required for development of gravity-sensing otoconia in the vestibular system, as forming a proton-selective ion channel. We found that murine OTOP1 is enriched in acid-detecting taste receptor cells and is required for their zinc-sensitive proton conductance. Two related murine genes, Otop2 and Otop3, and a Drosophila ortholog also encode proton channels. Evolutionary conservation of the gene family and its widespread tissue distribution suggest a broad role for proton channels in physiology and pathophysiology.
Collapse
Affiliation(s)
- Yu-Hsiang Tu
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Alexander J Cooper
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Bochuan Teng
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Rui B Chang
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Daniel J Artiga
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Heather N Turner
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Eric M Mulhall
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Wenlei Ye
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA.
| | - Andrew D Smith
- Department of Biological Sciences, Section of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Emily R Liman
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA. .,Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| |
Collapse
|
13
|
Hołubowicz R, Wojtas M, Taube M, Kozak M, Ożyhar A, Dobryszycki P. Effect of calcium ions on structure and stability of the C1q-like domain of otolin-1 from human and zebrafish. FEBS J 2017; 284:4278-4297. [DOI: 10.1111/febs.14308] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/17/2017] [Accepted: 10/24/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Rafał Hołubowicz
- Department of Biochemistry; Faculty of Chemistry; Wroclaw University of Science and Technology; Poland
| | - Magdalena Wojtas
- Department of Biochemistry; Faculty of Chemistry; Wroclaw University of Science and Technology; Poland
| | - Michał Taube
- Department of Macromolecular Physics; Faculty of Physics; A. Mickiewicz University; Poznan Poland
| | - Maciej Kozak
- Department of Macromolecular Physics; Faculty of Physics; A. Mickiewicz University; Poznan Poland
| | - Andrzej Ożyhar
- Department of Biochemistry; Faculty of Chemistry; Wroclaw University of Science and Technology; Poland
| | - Piotr Dobryszycki
- Department of Biochemistry; Faculty of Chemistry; Wroclaw University of Science and Technology; Poland
| |
Collapse
|
14
|
Burghoff S, Willberg W, Schrader J. Identification of extracellularly phosphorylated membrane proteins. Proteomics 2015; 15:3310-4. [DOI: 10.1002/pmic.201400595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 05/11/2015] [Accepted: 07/01/2015] [Indexed: 01/26/2023]
Affiliation(s)
- Sandra Burghoff
- Department of Molecular Cardiology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
| | - Wibke Willberg
- Department of Molecular Cardiology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
| | - Jürgen Schrader
- Department of Molecular Cardiology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
| |
Collapse
|
15
|
Gopinathan G, Jin T, Liu M, Li S, Atsawasuwan P, Galang MT, Allen M, Luan X, Diekwisch TGH. The expanded amelogenin polyproline region preferentially binds to apatite versus carbonate and promotes apatite crystal elongation. Front Physiol 2014; 5:430. [PMID: 25426079 PMCID: PMC4227485 DOI: 10.3389/fphys.2014.00430] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 10/16/2014] [Indexed: 01/23/2023] Open
Abstract
The transition from invertebrate calcium carbonate-based calcite and aragonite exo- and endoskeletons to the calcium phosphate-based vertebrate backbones and jaws composed of microscopic hydroxyapatite crystals is one of the great revolutions in the evolution of terrestrial organisms. To identify potential factors that might have played a role in such a transition, three key domains of the vertebrate tooth enamel protein amelogenin were probed for calcium mineral/protein interactions and their ability to promote calcium phosphate and calcium carbonate crystal growth. Under calcium phosphate crystal growth conditions, only the carboxy-terminus augmented polyproline repeat peptide, but not the N-terminal peptide nor the polyproline repeat peptide alone, promoted the formation of thin and parallel crystallites resembling those of bone and initial enamel. In contrast, under calcium carbonate crystal growth conditions, all three amelogenin-derived polypeptides caused calcium carbonate to form fused crystalline conglomerates. When examined for long-term crystal growth, polyproline repeat peptides of increasing length promoted the growth of shorter calcium carbonate crystals with broader basis, contrary to the positive correlation between polyproline repeat element length and apatite mineralization published earlier. To determine whether the positive correlation between polyproline repeat element length and apatite crystal growth versus the inverse correlation between polyproline repeat length and calcium carbonate crystal growth were related to the binding affinity of the polyproline domain to either apatite or carbonate, a parallel series of calcium carbonate and calcium phosphate/apatite protein binding studies was conducted. These studies demonstrated a remarkable binding affinity between the augmented amelogenin polyproline repeat region and calcium phosphates, and almost no binding to calcium carbonates. In contrast, the amelogenin N-terminus bound to both carbonate and apatite, but preferentially to calcium carbonate. Together, these studies highlight the specific binding affinity of the augmented amelogenin polyproline repeat region to calcium phosphates versus calcium carbonate, and its unique role in the growth of thin apatite crystals as they occur in vertebrate biominerals. Our data suggest that the rise of apatite-based biominerals in vertebrates might have been facilitated by a rapid evolution of specialized polyproline repeat proteins flanked by a charged domain, resulting in apatite crystals with reduced width, increased length, and tailored biomechanical properties.
Collapse
Affiliation(s)
- Gokul Gopinathan
- Oral Biology, University of Illinois at Chicago Brodie Laboratory for Craniofacial Genetics, University of Illinois at Chicago College of Dentistry Chicago, IL, USA
| | - Tianquan Jin
- Biocytogen, One Innovation Drive Worcester, MA, USA
| | - Min Liu
- Department of Periodontology, Stomatological Hospital, Jilin University Changchun, China
| | - Steve Li
- Oral Biology, University of Illinois at Chicago Brodie Laboratory for Craniofacial Genetics, University of Illinois at Chicago College of Dentistry Chicago, IL, USA
| | - Phimon Atsawasuwan
- University of Illinois at Chicago Department of Orthodontics, University of Illinois at Chicago College of Dentistry Chicago, IL, USA
| | - Maria-Therese Galang
- University of Illinois at Chicago Department of Orthodontics, University of Illinois at Chicago College of Dentistry Chicago, IL, USA
| | - Michael Allen
- Department of Medicine, University of Chicago Chicago, IL, USA
| | - Xianghong Luan
- Oral Biology, University of Illinois at Chicago Brodie Laboratory for Craniofacial Genetics, University of Illinois at Chicago College of Dentistry Chicago, IL, USA
| | - Thomas G H Diekwisch
- Oral Biology, University of Illinois at Chicago Brodie Laboratory for Craniofacial Genetics, University of Illinois at Chicago College of Dentistry Chicago, IL, USA
| |
Collapse
|
16
|
Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014; 244:239-53. [PMID: 25255879 DOI: 10.1002/dvdy.24195] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
Collapse
Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
| | | | | | | |
Collapse
|
17
|
Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014. [PMID: 25255879 DOI: 10.1002/dvdy.24195(2014)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
Collapse
Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
| | | | | | | |
Collapse
|
18
|
Rafiq K, Shashikant T, McManus CJ, Ettensohn CA. Genome-wide analysis of the skeletogenic gene regulatory network of sea urchins. Development 2014; 141:950-61. [PMID: 24496631 DOI: 10.1242/dev.105585] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A central challenge of developmental and evolutionary biology is to understand the transformation of genetic information into morphology. Elucidating the connections between genes and anatomy will require model morphogenetic processes that are amenable to detailed analysis of cell/tissue behaviors and to systems-level approaches to gene regulation. The formation of the calcified endoskeleton of the sea urchin embryo is a valuable experimental system for developing such an integrated view of the genomic regulatory control of morphogenesis. A transcriptional gene regulatory network (GRN) that underlies the specification of skeletogenic cells (primary mesenchyme cells, or PMCs) has recently been elucidated. In this study, we carried out a genome-wide analysis of mRNAs encoded by effector genes in the network and uncovered transcriptional inputs into many of these genes. We used RNA-seq to identify >400 transcripts differentially expressed by PMCs during gastrulation, when these cells undergo a striking sequence of behaviors that drives skeletal morphogenesis. Our analysis expanded by almost an order of magnitude the number of known (and candidate) downstream effectors that directly mediate skeletal morphogenesis. We carried out genome-wide analysis of (1) functional targets of Ets1 and Alx1, two pivotal, early transcription factors in the PMC GRN, and (2) functional targets of MAPK signaling, a pathway that plays an essential role in PMC specification. These studies identified transcriptional inputs into >200 PMC effector genes. Our work establishes a framework for understanding the genomic regulatory control of a major morphogenetic process and has important implications for reconstructing the evolution of biomineralization in metazoans.
Collapse
Affiliation(s)
- Kiran Rafiq
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | | | | | | |
Collapse
|
19
|
Wang GX, Cho KW, Uhm M, Hu CR, Li S, Cozacov Z, Xu AE, Cheng JX, Saltiel AR, Lumeng CN, Lin JD. Otopetrin 1 protects mice from obesity-associated metabolic dysfunction through attenuating adipose tissue inflammation. Diabetes 2014; 63:1340-52. [PMID: 24379350 PMCID: PMC3964504 DOI: 10.2337/db13-1139] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Chronic low-grade inflammation is emerging as a pathogenic link between obesity and metabolic disease. Persistent immune activation in white adipose tissue (WAT) impairs insulin sensitivity and systemic metabolism, in part, through the actions of proinflammatory cytokines. Whether obesity engages an adaptive mechanism to counteract chronic inflammation in adipose tissues has not been elucidated. Here we identified otopetrin 1 (Otop1) as a component of a counterinflammatory pathway that is induced in WAT during obesity. Otop1 expression is markedly increased in obese mouse WAT and is stimulated by tumor necrosis factor-α in cultured adipocytes. Otop1 mutant mice respond to high-fat diet with pronounced insulin resistance and hepatic steatosis, accompanied by augmented adipose tissue inflammation. Otop1 attenuates interferon-γ (IFN-γ) signaling in adipocytes through selective downregulation of the transcription factor STAT1. Using a tagged vector, we found that Otop1 physically interacts with endogenous STAT1. Thus, Otop1 defines a unique target of cytokine signaling that attenuates obesity-induced adipose tissue inflammation and plays an adaptive role in maintaining metabolic homeostasis in obesity.
Collapse
Affiliation(s)
- Guo-Xiao Wang
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Kae Won Cho
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI
| | - Maeran Uhm
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Chun-Rui Hu
- Weldon School of Biomedical Engineering, Department of Chemistry, Purdue University, West Lafayette, IN
| | - Siming Li
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Zoharit Cozacov
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Acer E. Xu
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Department of Chemistry, Purdue University, West Lafayette, IN
| | - Alan R. Saltiel
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Carey N. Lumeng
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI
| | - Jiandie D. Lin
- Life Sciences Institute, University of Michigan Medical School, Ann Arbor, MI
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Corresponding author: Jiandie D. Lin,
| |
Collapse
|
20
|
Computational Approaches and Resources in Single Amino Acid Substitutions Analysis Toward Clinical Research. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2014; 94:365-423. [DOI: 10.1016/b978-0-12-800168-4.00010-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
21
|
Hyrc KL, Minta A, Escamilla PR, Chan PPL, Meshik XA, Goldberg MP. Synthesis and properties of Asante Calcium Red--a novel family of long excitation wavelength calcium indicators. Cell Calcium 2013; 54:320-33. [PMID: 24017967 DOI: 10.1016/j.ceca.2013.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 07/29/2013] [Accepted: 08/01/2013] [Indexed: 10/26/2022]
Abstract
Although many synthetic calcium indicators are available, a search for compounds with improved characteristics continues. Here, we describe the synthesis and properties of Asante Calcium Red-1 (ACR-1) and its low affinity derivative (ACR-1-LA) created by linking BAPTA to seminaphthofluorescein. The indicators combine a visible light (450-540 nm) excitation with deep-red fluorescence (640 nm). Upon Ca2+ binding, the indicators raise their fluorescence with longer excitation wavelengths producing higher responses. Although the changes occur without any spectral shifts, it is possible to ratio Ca(2+)-dependent (640 nm) and quasi-independent (530 nm) emission when using visible (< 490 nm) or multiphoton (∼780 nm) excitation. Therefore, both probes can be used as single wavelength or, less dynamic, ratiometric indicators. Long indicator emission might allow easy [Ca2+]i measurement in GFP expressing cells. The indicators bind Ca2+ with either high (Kd = 0.49 ± 0.07 μM; ACR-1) or low affinity (Kd = 6.65 ± 0.13 μM; ACR-1-LA). Chelating Zn2+ (Kd = 0.38 ± 0.02 nM) or Mg2+ (Kd∼5mM) slightly raises and binding Co2+ quenches dye fluorescence. New indicators are somewhat pH-sensitive (pKa = 6.31 ± 0.07), but fairly resistant to bleaching. The probes are rather dim, which combined with low AM ester loading efficiency, might complicate in situ imaging. Despite potential drawbacks, ACR-1 and ACR-1-LA are promising new calcium indicators.
Collapse
Affiliation(s)
- Krzysztof L Hyrc
- The Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA; Alafi Neuroimaging Laboratory, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | | | | | | | | | | |
Collapse
|
22
|
Inner ear supporting cells: rethinking the silent majority. Semin Cell Dev Biol 2013; 24:448-59. [PMID: 23545368 DOI: 10.1016/j.semcdb.2013.03.009] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/21/2013] [Indexed: 11/21/2022]
Abstract
Sensory epithelia of the inner ear contain two major cell types: hair cells and supporting cells. It has been clear for a long time that hair cells play critical roles in mechanoreception and synaptic transmission. In contrast, until recently the more abundant supporting cells were viewed as serving primarily structural and homeostatic functions. In this review, we discuss the growing information about the roles that supporting cells play in the development, function and maintenance of the inner ear, their activities in pathological states, their potential for hair cell regeneration, and the mechanisms underlying these processes.
Collapse
|
23
|
Analyzing effects of naturally occurring missense mutations. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2012; 2012:805827. [PMID: 22577471 PMCID: PMC3346971 DOI: 10.1155/2012/805827] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 11/17/2022]
Abstract
Single-point mutation in genome, for example, single-nucleotide polymorphism (SNP) or rare genetic mutation, is the change of a single nucleotide for another in the genome sequence. Some of them will produce an amino acid substitution in the corresponding protein sequence (missense mutations); others will not. This paper focuses on genetic mutations resulting in a change in the amino acid sequence of the corresponding protein and how to assess their effects on protein wild-type characteristics. The existing methods and approaches for predicting the effects of mutation on protein stability, structure, and dynamics are outlined and discussed with respect to their underlying principles. Available resources, either as stand-alone applications or webservers, are pointed out as well. It is emphasized that understanding the molecular mechanisms behind these effects due to these missense mutations is of critical importance for detecting disease-causing mutations. The paper provides several examples of the application of 3D structure-based methods to model the effects of protein stability and protein-protein interactions caused by missense mutations as well.
Collapse
|