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Sato Y, Yoshimura K, Matsuda K, Haraguchi T, Marumo A, Yamagishi M, Sato S, Ito K, Yajima J. Membrane-bound myosin IC drives the chiral rotation of the gliding actin filament around its longitudinal axis. Sci Rep 2023; 13:19908. [PMID: 37963943 PMCID: PMC10646037 DOI: 10.1038/s41598-023-47125-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 11/09/2023] [Indexed: 11/16/2023] Open
Abstract
Myosin IC, a single-headed member of the myosin I family, specifically interacts with anionic phosphatidylinositol 4,5-bisphosphate (PI[4,5]P2) in the cell membrane via the pleckstrin homology domain located in the myosin IC tail. Myosin IC is widely expressed and physically links the cell membrane to the actin cytoskeleton; it plays various roles in membrane-associated physiological processes, including establishing cellular chirality, lipid transportation, and mechanosensing. In this study, we evaluated the motility of full-length myosin IC of Drosophila melanogaster via the three-dimensional tracking of quantum dots bound to actin filaments that glided over a membrane-bound myosin IC-coated surface. The results revealed that myosin IC drove a left-handed rotational motion in the gliding actin filament around its longitudinal axis, indicating that myosin IC generated a torque perpendicular to the gliding direction of the actin filament. The quantification of the rotational motion of actin filaments on fluid membranes containing different PI(4,5)P2 concentrations revealed that the rotational pitch was longer at lower PI(4,5)P2 concentrations. These results suggest that the torque generated by membrane-bound myosin IC molecules can be modulated based on the phospholipid composition of the cell membrane.
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Affiliation(s)
- Yusei Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Kohei Yoshimura
- Department of Biology, Graduate School of Science, Chiba University, 1-33, Inage, Chiba, Japan
| | - Kyohei Matsuda
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Takeshi Haraguchi
- Department of Biology, Graduate School of Science, Chiba University, 1-33, Inage, Chiba, Japan
| | - Akisato Marumo
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Masahiko Yamagishi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Suguru Sato
- Department of Biology, Graduate School of Science, Chiba University, 1-33, Inage, Chiba, Japan
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, 1-33, Inage, Chiba, Japan.
| | - Junichiro Yajima
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
- Komaba Institute for Science, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
- Research Center for Complex Systems Biology, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
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2
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Arif E, Solanki AK, Srivastava P, Rahman B, Tash BR, Holzman LB, Janech MG, Martin R, Knölker HJ, Fitzgibbon WR, Deng P, Budisavljevic MN, Syn WK, Wang C, Lipschutz JH, Kwon SH, Nihalani D. The motor protein Myo1c regulates transforming growth factor-β-signaling and fibrosis in podocytes. Kidney Int 2019; 96:139-158. [PMID: 31097328 DOI: 10.1016/j.kint.2019.02.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/07/2019] [Accepted: 02/14/2019] [Indexed: 01/19/2023]
Abstract
Transforming growth factor-β (TGF-β) is known to play a critical role in the pathogenesis of many progressive podocyte diseases. However, the molecular mechanisms regulating TGF-β signaling in podocytes remain unclear. Using a podocyte-specific myosin (Myo)1c knockout, we demonstrate whether Myo1c is critical for TGF-β-signaling in podocyte disease pathogenesis. Specifically, podocyte-specific Myo1c knockout mice were resistant to fibrotic injury induced by Adriamycin or nephrotoxic serum. Further, loss of Myo1c also protected from injury in the TGF-β-dependent unilateral ureteral obstruction mouse model of renal interstitial fibrosis. Mechanistic analyses showed that loss of Myo1c significantly blunted TGF-β signaling through downregulation of canonical and non-canonical TGF-β pathways. Interestingly, nuclear rather than the cytoplasmic Myo1c was found to play a central role in controlling TGF-β signaling through transcriptional regulation. Differential expression analysis of nuclear Myo1c-associated gene promoters showed that nuclear Myo1c targeted the TGF-β responsive gene growth differentiation factor (GDF)-15 and directly bound to the GDF-15 promoter. Importantly, GDF15 was found to be involved in podocyte pathogenesis, where GDF15 was upregulated in glomeruli of patients with focal segmental glomerulosclerosis. Thus, Myo1c-mediated regulation of TGF-β-responsive genes is central to the pathogenesis of podocyte injury. Hence, inhibiting this process may have clinical application in treating podocytopathies.
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Affiliation(s)
- Ehtesham Arif
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ashish K Solanki
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Pankaj Srivastava
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Bushra Rahman
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Brian R Tash
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Lawrence B Holzman
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael G Janech
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA; College of Charleston, Charleston, South Carolina, USA
| | - René Martin
- Department of Chemistry, TU Dresden, Dresden, Germany
| | | | - Wayne R Fitzgibbon
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Peifeng Deng
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Milos N Budisavljevic
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Wing-Kin Syn
- Department of Gastroenterology & Hepatology, Medical University of South Carolina, Charleston, South Carolina, USA; Section of Gastroenterology, Ralph H Johnson VA Medical Center, Charleston, South Carolina, USA; Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country, (UPV/EHU), Vizcaya, Spain
| | - Cindy Wang
- Department of Gastroenterology & Hepatology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Joshua H Lipschutz
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Sang-Ho Kwon
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Deepak Nihalani
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA.
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3
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McLean WJ, McLean DT, Eatock RA, Edge ASB. Distinct capacity for differentiation to inner ear cell types by progenitor cells of the cochlea and vestibular organs. Development 2016; 143:4381-4393. [PMID: 27789624 DOI: 10.1242/dev.139840] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 10/11/2016] [Indexed: 01/16/2023]
Abstract
Disorders of hearing and balance are most commonly associated with damage to cochlear and vestibular hair cells or neurons. Although these cells are not capable of spontaneous regeneration, progenitor cells in the hearing and balance organs of the neonatal mammalian inner ear have the capacity to generate new hair cells after damage. To investigate whether these cells are restricted in their differentiation capacity, we assessed the phenotypes of differentiated progenitor cells isolated from three compartments of the mouse inner ear - the vestibular and cochlear sensory epithelia and the spiral ganglion - by measuring electrophysiological properties and gene expression. Lgr5+ progenitor cells from the sensory epithelia gave rise to hair cell-like cells, but not neurons or glial cells. Newly created hair cell-like cells had hair bundle proteins, synaptic proteins and membrane proteins characteristic of the compartment of origin. PLP1+ glial cells from the spiral ganglion were identified as neural progenitors, which gave rise to neurons, astrocytes and oligodendrocytes, but not hair cells. Thus, distinct progenitor populations from the neonatal inner ear differentiate to cell types associated with their organ of origin.
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Affiliation(s)
- Will J McLean
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA.,Eaton-Peabody Laboratories of Auditory Physiology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Program in Speech and Hearing Bioscience and Technology, Division of Health Sciences and Technology, Harvard & MIT, Cambridge, MA 02139, USA
| | - Dalton T McLean
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA.,Eaton-Peabody Laboratories of Auditory Physiology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
| | - Ruth Anne Eatock
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
| | - Albert S B Edge
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA .,Eaton-Peabody Laboratories of Auditory Physiology, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA.,Program in Speech and Hearing Bioscience and Technology, Division of Health Sciences and Technology, Harvard & MIT, Cambridge, MA 02139, USA.,Harvard Stem Cell Institute, Cambridge, MA 02138, USA
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4
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Du Y, Chen Y, Wang F, Gu L. miR-137 plays tumor suppressor roles in gastric cancer cell lines by targeting KLF12 and MYO1C. Tumour Biol 2016; 37:13557-13569. [PMID: 27468717 DOI: 10.1007/s13277-016-5199-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/13/2016] [Indexed: 12/12/2022] Open
Abstract
Aberrant expression of miR-137 has been reported in many kinds of cancers, but its mechanisms seem to be diversely. In the present study, we compared the expression level of miR-137 in 18 paired gastric cancer (GC) samples and surgical margin (SM) samples by RNA extraction and quantitative real-time PCR (QRT-PCR). Then, we investigated the effects of miR-137 on cell proliferation, cell cycle, and cell migration separately by cell growth counting assay, cell cycle analysis, and transwell assay. Candidate targets of miR-137 were selected by biological information analysis from the intersection of miRDB, Pictar, and TarScan. Finally, mRNA and protein expression level of Krűppel-like factor 12 (KLF12) and Myosin 1C (MYO1C) were tested by QRT-PCR and western blotting assay, followed by the Luciferase reporter assay to investigate the direct interaction between them and miR-137. The results showed that miR-137 was down-regulated in GC samples than in SM samples. The expression level of miR-137 was significantly higher in patients without the vascular embolus than those with vascular embolus. And the overall survival time of patients with high miR-137 expression was longer than those with low miR-137 expression. Over expression of miR-137 could inhibit the cell migration, proliferation, and promote cell cycle arrest in G0/G1 stage in BGC-823 and SGC-7901 cell lines. KLF12 and MYO1C might be the candidate target genes of miR-137 with direct interactions between them and miR-137. In conclusion, miR-137 plays tumor suppressor roles in gastric cancer cell lines by targeting KLF12 and MYO1C.
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Affiliation(s)
- Yantao Du
- Ningbo Institute of Medical Science, Yang-Shan-Lu, No.42-46, Jiangbei District, Ningbo, China.
| | - Yichen Chen
- Ningbo Institute of Medical Science, Yang-Shan-Lu, No.42-46, Jiangbei District, Ningbo, China
| | - Furong Wang
- Ningbo Institute of Medical Science, Yang-Shan-Lu, No.42-46, Jiangbei District, Ningbo, China
| | - Liankun Gu
- Peking University Cancer Hospital and Institute, Fu-Cheng-Lu, No.52, Haidian District, Beijing, China
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5
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Class I myosins have overlapping and specialized functions in left-right asymmetric development in Drosophila. Genetics 2015; 199:1183-99. [PMID: 25659376 DOI: 10.1534/genetics.115.174698] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 02/04/2015] [Indexed: 11/18/2022] Open
Abstract
The class I myosin genes are conserved in diverse organisms, and their gene products are involved in actin dynamics, endocytosis, and signal transduction. Drosophila melanogaster has three class I myosin genes, Myosin 31DF (Myo31DF), Myosin 61F (Myo61F), and Myosin 95E (Myo95E). Myo31DF, Myo61F, and Myo95E belong to the Myosin ID, Myosin IC, and Myosin IB families, respectively. Previous loss-of-function analyses of Myo31DF and Myo61F revealed important roles in left-right (LR) asymmetric development and enterocyte maintenance, respectively. However, it was difficult to elucidate their roles in vivo, because of potential redundant activities. Here we generated class I myosin double and triple mutants to address this issue. We found that the triple mutant was viable and fertile, indicating that all three class I myosins were dispensable for survival. A loss-of-function analysis revealed further that Myo31DF and Myo61F, but not Myo95E, had redundant functions in promoting the dextral LR asymmetric development of the male genitalia. Myo61F overexpression is known to antagonize the dextral activity of Myo31DF in various Drosophila organs. Thus, the LR-reversing activity of overexpressed Myo61F may not reflect its physiological function. The endogenous activity of Myo61F in promoting dextral LR asymmetric development was observed in the male genitalia, but not the embryonic gut, another LR asymmetric organ. Thus, Myo61F and Myo31DF, but not Myo95E, play tissue-specific, redundant roles in LR asymmetric development. Our studies also revealed differential colocalization of the class I myosins with filamentous (F)-actin in the brush border of intestinal enterocytes.
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6
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Arif E, Kumari B, Wagner MC, Zhou W, Holzman LB, Nihalani D. Myo1c is an unconventional myosin required for zebrafish glomerular development. Kidney Int 2013; 84:1154-65. [PMID: 23715127 PMCID: PMC3844053 DOI: 10.1038/ki.2013.201] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 03/14/2013] [Accepted: 03/21/2013] [Indexed: 12/17/2022]
Abstract
The targeting and organization of podocyte slit diaphragm proteins nephrin and neph1 is critical for development and maintenance of a functional glomerular filtration barrier. Myo1c is a non-muscle myosin motor protein that interacts directly with nephrin and neph1 and mediates their intracellular transport to the podocyte intercellular junction. Here we investigated the necessity of Myo1c in podocyte development using zebrafish as a model system. Immunofluorescence microscopy and in situ RNA hybridization analysis of zebrafish embryos showed that Myo1c is widely expressed in various tissues including the zebrafish glomerulus. Knockdown of the Myo1c gene in zebrafish using antisense morpholino derivatives resulted in an abnormal developmental phenotype that included pericardial edema and dilated renal tubules. Ultra-structural analysis of the glomerulus in Myo1c depleted zebrafish showed abnormal podocyte morphology and absence of the slit diaphragm. Consistent with these observations, the glomerular filter permeability appeared altered in zebrafish in which Myo1c expression was attenuated. The specificity of Myo1c knockdown was confirmed by a rescue experiment in which co-injection of Myo1c morpholino derivatives with orthologous Myo1c mRNA prepared from mouse cDNA lessened phenotypic abnormalities including edema in Myo1c morphants. Thus, our results demonstrate that Myo1c is necessary for podocyte morphogenesis.
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Affiliation(s)
- Ehtesham Arif
- Renal Electrolyte and Hypertension Division, Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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7
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Pyrpassopoulos S, Feeser EA, Mazerik JN, Tyska MJ, Ostap EM. Membrane-bound myo1c powers asymmetric motility of actin filaments. Curr Biol 2012; 22:1688-92. [PMID: 22863317 PMCID: PMC3461085 DOI: 10.1016/j.cub.2012.06.069] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 06/08/2012] [Accepted: 06/27/2012] [Indexed: 12/31/2022]
Abstract
Class I myosins are molecular motors that link cellular membranes to the actin cytoskeleton and play roles in membrane tension generation, membrane dynamics, and mechanosignal transduction. The widely expressed myosin-Ic (myo1c) isoform binds tightly to phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] via a pleckstrin homology domain located in the myo1c tail, which is important for its proper cellular localization. In this study, we found that myo1c can power actin motility on fluid membranes composed of physiological concentrations of PtdIns(4,5)P(2) and that this motility is inhibited by high concentrations of anionic phospholipids. Strikingly, this motility occurs along curved paths in a counterclockwise direction (i.e., the actin filaments turn in leftward circles). A biotinylated myo1c construct containing only the motor domain and the lever arm anchored via streptavidin on a membrane containing biotinylated lipid can also generate asymmetric motility, suggesting that the tail domain is not required for the counterclockwise turning. We found that the ability to produce counterclockwise motility is not a universal characteristic of myosin-I motors, as membrane-bound myosin-Ia (myo1a) and myosin-Ib (myo1b) are able to power actin gliding, but the actin gliding has no substantial turning bias. This work reveals a possible mechanism for establishing asymmetry in relationship to the plasma membrane.
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Affiliation(s)
- Serapion Pyrpassopoulos
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia PA 19104-6085
| | - Elizabeth A. Feeser
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia PA 19104-6085
| | - Jessica N. Mazerik
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - E. Michael Ostap
- The Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia PA 19104-6085
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8
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Myosin IC generates power over a range of loads via a new tension-sensing mechanism. Proc Natl Acad Sci U S A 2012; 109:E2433-40. [PMID: 22908250 DOI: 10.1073/pnas.1207811109] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosin IC (myo1c), a widely expressed motor protein that links the actin cytoskeleton to cell membranes, has been associated with numerous cellular processes, including insulin-stimulated transport of GLUT4, mechanosensation in sensory hair cells, endocytosis, transcription of DNA in the nucleus, exocytosis, and membrane trafficking. The molecular role of myo1c in these processes has not been defined, so to better understand myo1c function, we utilized ensemble kinetic and single-molecule techniques to probe myo1c's biochemical and mechanical properties. Utilizing a myo1c construct containing the motor and regulatory domains, we found the force dependence of the actin-attachment lifetime to have two distinct regimes: a force-independent regime at forces < 1 pN, and a highly force-dependent regime at higher loads. In this force-dependent regime, forces that resist the working stroke increase the actin-attachment lifetime. Unexpectedly, the primary force-sensitive transition is the isomerization that follows ATP binding, not ADP release as in other slow myosins. This force-sensing behavior is unique amongst characterized myosins and clearly demonstrates mechanochemical diversity within the myosin family. Based on these results, we propose that myo1c functions as a slow transporter rather than a tension-sensitive anchor.
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9
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Auditory and vestibular hair cell stereocilia: relationship between functionality and inner ear disease. The Journal of Laryngology & Otology 2011; 125:991-1003. [PMID: 21774850 DOI: 10.1017/s0022215111001459] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The stereocilia of the inner ear are unique cellular structures which correlate anatomically with distinct cochlear functions, including mechanoelectrical transduction, cochlear amplification, adaptation, frequency selectivity and tuning. Their function is impaired by inner ear stressors, by various types of hereditary deafness, syndromic hearing loss and inner ear disease (e.g. Ménière's disease). The anatomical and physiological characteristics of stereocilia are discussed in relation to inner ear malfunctions.
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Lin T, Greenberg MJ, Moore JR, Ostap EM. A hearing loss-associated myo1c mutation (R156W) decreases the myosin duty ratio and force sensitivity. Biochemistry 2011; 50:1831-8. [PMID: 21265502 PMCID: PMC3059334 DOI: 10.1021/bi1016777] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
myo1c is a member of the myosin superfamily that has been proposed to function as the adaptation motor in vestibular and auditory hair cells. A recent study identified a myo1c point mutation (R156W) in a person with bilateral sensorineural hearing loss. This mutated residue is located at the start of the highly conserved switch 1 region, which is a crucial element for the binding of nucleotide. We characterized the key steps on the ATPase pathway at 37 °C using recombinant wild-type (myo1c(3IQ)) and mutant myo1c (R156W-myo1c(3IQ)) constructs that consist of the motor domain and three IQ motifs. The R156W mutation only moderately affects the rates of ATP binding, ATP-induced actomyosin dissociation, and ADP release. The actin-activated ATPase rate of the mutant is inhibited >4-fold, which is likely due to a decrease in the rate of phosphate release. The rate of actin gliding, as measured by the in vitro motility assay, is unaffected by the mutation at high myosin surface densities, but the rate of actin gliding is substantially reduced at low surface densities of R156W-myo1c(3IQ). We used a frictional loading assay to measure the affect of resisting forces on the rate of actin gliding and found that R156W-myo1c(3IQ) is less force-sensitive than myo1c(3IQ). Taken together, these results indicate that myo1c with the R156W mutation has a lower duty ratio than the wild-type protein and motile properties that are less sensitive to resisting forces.
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Affiliation(s)
- Tianming Lin
- Pennsylvania Muscle Institute and Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Michael J. Greenberg
- Pennsylvania Muscle Institute and Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Jeffrey R. Moore
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - E. Michael Ostap
- Pennsylvania Muscle Institute and Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
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11
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Komaba S, Coluccio LM. Localization of myosin 1b to actin protrusions requires phosphoinositide binding. J Biol Chem 2010; 285:27686-93. [PMID: 20610386 DOI: 10.1074/jbc.m109.087270] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin 1b (Myo1b), a class I myosin, is a widely expressed, single-headed, actin-associated molecular motor. Transient kinetic and single-molecule studies indicate that it is kinetically slow and responds to tension. Localization and subcellular fractionation studies indicate that Myo1b associates with the plasma membrane and certain subcellular organelles such as endosomes and lysosomes. Whether Myo1b directly associates with membranes is unknown. We demonstrate here that full-length rat Myo1b binds specifically and with high affinity to phosphatidylinositol 4,5-bisphosphate (PIP(2)) and phosphatidylinositol 3,4,5-triphosphate (PIP(3)), two phosphoinositides that play important roles in cell signaling. Binding is not Ca(2+)-dependent and does not involve the calmodulin-binding IQ region in the neck domain of Myo1b. Furthermore, the binding site is contained entirely within the C-terminal tail region, which contains a putative pleckstrin homology domain. Single mutations in the putative pleckstrin homology domain abolish binding of the tail domain of Myo1b to PIP(2) and PIP(3) in vitro. These same mutations alter the distribution of Myc-tagged Myo1b at membrane protrusions in HeLa cells where PIP(2) localizes. In addition, we found that motor activity is required for Myo1b localization in filopodia. These results suggest that binding of Myo1b to phosphoinositides plays an important role in vivo by regulating localization to actin-enriched membrane projections.
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Affiliation(s)
- Shigeru Komaba
- Boston Biomedical Research Institute, Watertown, Massachusetts 02472, USA
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12
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Abstract
Myosin-Is are molecular motors that link cellular membranes to the actin cytoskeleton, where they play roles in mechano-signal transduction and membrane trafficking. Some myosin-Is are proposed to act as force sensors, dynamically modulating their motile properties in response to changes in tension. In this study, we examined force sensing by the widely expressed myosin-I isoform, myo1b, which is alternatively spliced in its light chain binding domain (LCBD), yielding proteins with lever arms of different lengths. We found the actin-detachment kinetics of the splice isoforms to be extraordinarily tension-sensitive, with the magnitude of tension sensitivity to be related to LCBD splicing. Thus, in addition to regulating step-size, motility rates, and myosin activation, the LCBD is a key regulator of force sensing. We also found that myo1b is substantially more tension-sensitive than other myosins with similar length lever arms, indicating that different myosins have different tension-sensitive transitions.
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13
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Olety B, Wälte M, Honnert U, Schillers H, Bähler M. Myosin 1G (Myo1G) is a haematopoietic specific myosin that localises to the plasma membrane and regulates cell elasticity. FEBS Lett 2009; 584:493-9. [PMID: 19968988 DOI: 10.1016/j.febslet.2009.11.096] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 11/10/2009] [Accepted: 11/30/2009] [Indexed: 11/19/2022]
Abstract
Immune cells navigate through different environments where they experience different mechanical forces. Responses to external forces are determined by the mechanical properties of a cell and they depend to a large extent on the actin-rich cell cortex. We report here that Myo1G, a previously uncharacterised member of class I myosins, is expressed specifically in haematopoietic tissues and cells. It is associated with the plasma membrane. This association is dependent on a conserved PH-domain-like myosin I tail homology motif and the head domain. However, the head domain does not need to be a functional motor. Knockdown of Myo1G in Jurkat cells decreased cell elasticity significantly. We propose that Myo1G regulates cell elasticity by deformations of the actin network at the cell cortex.
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Affiliation(s)
- Balaji Olety
- Institute of General Zoology and Genetics, Westfalian Wilhelms-University Münster, Münster, Germany
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14
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Zheng J, Anderson CT, Miller KK, Cheatham M, Dallos P. Identifying components of the hair-cell interactome involved in cochlear amplification. BMC Genomics 2009; 10:127. [PMID: 19320974 PMCID: PMC2669096 DOI: 10.1186/1471-2164-10-127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 03/25/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although outer hair cells (OHCs) play a key role in cochlear amplification, it is not fully understood how they amplify sound signals by more than 100 fold. Two competing or possibly complementary mechanisms, stereocilia-based and somatic electromotility-based amplification, have been considered. Lacking knowledge about the exceptionally rich protein networks in the OHC plasma membrane, as well as related protein-protein interactions, limits our understanding of cochlear function. Therefore, we focused on finding protein partners for two important membrane proteins: Cadherin 23 (cdh23) and prestin. Cdh23 is one of the tip-link proteins involved in transducer function, a key component of mechanoelectrical transduction and stereocilia-based amplification. Prestin is a basolateral membrane protein responsible for OHC somatic electromotility. RESULTS Using the membrane-based yeast two-hybrid system to screen a newly built cDNA library made predominantly from OHCs, we identified two completely different groups of potential protein partners using prestin and cdh23 as bait. These include both membrane bound and cytoplasmic proteins with 12 being de novo gene products with unknown function(s). In addition, some of these genes are closely associated with deafness loci, implying a potentially important role in hearing. The most abundant prey for prestin (38%) is composed of a group of proteins involved in electron transport, which may play a role in OHC survival. The most abundant group of cdh23 prey (55%) contains calcium-binding domains. Since calcium performs an important role in hair cell mechanoelectrical transduction and amplification, understanding the interactions between cdh23 and calcium-binding proteins should increase our knowledge of hair cell function at the molecular level. CONCLUSION The results of this study shed light on some protein networks in cochlear hair cells. Not only was a group of de novo genes closely associated with known deafness loci identified, but the data also indicate that the hair cell tip link interacts directly with calcium binding proteins. The OHC motor protein, prestin, also appears to be associated with electron transport proteins. These unanticipated results open potentially fruitful lines of investigation into the molecular basis of cochlear amplification.
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Affiliation(s)
- Jing Zheng
- Department of Communication Sciences and Disorders, The Hugh Knowles Center, Northwestern University, Evanston, IL 60208, USA.
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15
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Zadro C, Alemanno MS, Bellacchio E, Ficarella R, Donaudy F, Melchionda S, Zelante L, Rabionet R, Hilgert N, Estivill X, Van Camp G, Gasparini P, Carella M. Are MYO1C and MYO1F associated with hearing loss? Biochim Biophys Acta Mol Basis Dis 2008; 1792:27-32. [PMID: 19027848 DOI: 10.1016/j.bbadis.2008.10.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 10/15/2008] [Accepted: 10/17/2008] [Indexed: 11/15/2022]
Abstract
The role of myosins in the pathogenesis of hearing loss is well established: five genes encoding unconventional myosins and two genes encoding nonmuscle conventional myosins have so far been described to be essential for normal auditory function and mutations in these genes associated with hearing impairment. To better understand the role of this gene family we performed a mutational screening on two candidate genes, MYO1C and MYO1F, analyzing hundreds of patients, affected by bilateral sensorineural hearing loss and coming from different European countries. This research activity led to the identification of 6 heterozygous missense mutations in MYO1C and additional 5 heterozygous missense mutations in MYO1F. Homology modelling suggests that some of these mutations could have a potential influence on the structure of the ATP binding site and could probably affect the ATPase activity or the actin binding process of both myosins. This study suggests a role of the above mentioned myosin genes in the pathogenesis of hearing loss.
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Affiliation(s)
- Cristina Zadro
- Unit of Medical Genetics, Department of Reproductive Science and Development, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo" - Trieste, Italy
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16
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Manceva S, Lin T, Pham H, Lewis JH, Goldman YE, Ostap EM. Calcium regulation of calmodulin binding to and dissociation from the myo1c regulatory domain. Biochemistry 2007; 46:11718-26. [PMID: 17910470 PMCID: PMC2566900 DOI: 10.1021/bi700894h] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Myo1c is an unconventional myosin involved in cell signaling and membrane dynamics. Calcium binding to the regulatory-domain-associated calmodulin affects myo1c motor properties, but the kinetic details of this regulation are not fully understood. We performed actin gliding assays, ATPase measurements, fluorescence spectroscopy, and stopped-flow kinetics to determine the biochemical parameters that define the calmodulin-regulatory-domain interaction. We found calcium moderately increases the actin-activated ATPase activity and completely inhibits actin gliding. Addition of exogenous calmodulin in the presence of calcium fully restores the actin gliding rate. A fluorescently labeled calmodulin mutant (N111C) binds to recombinant peptides containing the myo1c IQ motifs at a diffusion-limited rate in the presence and absence of calcium. Measurements of calmodulin dissociation from the IQ motifs in the absence of calcium show that the calmodulin bound to the IQ motif adjacent to the motor domain (IQ1) has the slowest dissociation rate (0.0007 s-1), and the IQ motif adjacent to the tail domain (IQ3) has the fastest dissociation rate (0.5 s-1). When the complex is equilibrated with calcium, calmodulin dissociates most rapidly from IQ1 (60 s-1). However, this increased rate of dissociation is limited by a slow calcium-induced conformational change (3 s-1). Fluorescence anisotropy decay of fluorescently labeled N111C bound to myo1c did not depend appreciably on Ca2+. Our data suggest that the calmodulin bound to the IQ motif adjacent to the motor domain is rapidly exchangeable in the presence of calcium and is responsible for regulation of myo1c ATPase and motile activity.
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Affiliation(s)
| | | | | | | | | | - E. Michael Ostap
- *Corresponding author: E. Michael Ostap, Department of Physiology, University of Pennsylvania School of Medicine, B400 Richards Building, Philadelphia, PA 19104-6085, Phone: 215-573-9758, Fax: 215-573-1171,
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17
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Affiliation(s)
- Gerald Offer
- Department of Physiology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK.
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Batters C, Wallace MI, Coluccio LM, Molloy JE. A model of stereocilia adaptation based on single molecule mechanical studies of myosin I. Philos Trans R Soc Lond B Biol Sci 2005; 359:1895-905. [PMID: 15647165 PMCID: PMC1693475 DOI: 10.1098/rstb.2004.1559] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have used an optical tweezers-based apparatus to perform single molecule mechanical experiments using the unconventional myosins, Myo1b and Myo1c. The single-headed nature and slow ATPase kinetics of these myosins make them ideal for detailed studies of the molecular mechanism of force generation by acto-myosin. Myo1c exhibits several features that have not been seen using fast skeletal muscle myosin II. (i) The working stroke occurs in two, distinct phases, producing an initial 3 nm and then a further 1.5 nm of movement. (ii) Two types of binding interaction were observed: short-lived ATP-independent binding events that produced no movement and longer-lived, ATP-dependent events that produced a full working stroke. The stiffness of both types of interaction was similar. (iii) In a new type of experiment, using feedback to apply controlled displacements to a single acto-myosin cross-bridge, we found abrupt changes in force during attachment of the acto-Myo1b cross-bridge, a result that is consistent with the classical 'T2' behaviour of single muscle fibres. Given that these myosins might exhibit the classical T2 behaviour, we propose a new model to explain the slow phase of sensory adaptation of the hair cells of the inner ear.
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Affiliation(s)
- Christopher Batters
- Division of Physical Biochemistry, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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19
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Abstract
Introduction
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Affiliation(s)
- K C Holmes
- Max-Planck-Institute fur Medizinische Forschung, Jahnstrasse 29, Heidelberg D-61920, Germany
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