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Konietzny A, Han Y, Popp Y, van Bommel B, Sharma A, Delagrange P, Arbez N, Moutin MJ, Peris L, Mikhaylova M. Efficient axonal transport of endolysosomes relies on the balanced ratio of microtubule tyrosination and detyrosination. J Cell Sci 2024; 137:jcs261737. [PMID: 38525600 PMCID: PMC11112122 DOI: 10.1242/jcs.261737] [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: 10/18/2023] [Accepted: 03/14/2024] [Indexed: 03/26/2024] Open
Abstract
In neurons, the microtubule (MT) cytoskeleton forms the basis for long-distance protein transport from the cell body into and out of dendrites and axons. To maintain neuronal polarity, the axon initial segment (AIS) serves as a physical barrier, separating the axon from the somatodendritic compartment and acting as a filter for axonal cargo. Selective trafficking is further instructed by axonal enrichment of MT post-translational modifications, which affect MT dynamics and the activity of motor proteins. Here, we compared two knockout mouse lines lacking the respective enzymes for MT tyrosination and detyrosination, and found that both knockouts led to a shortening of the AIS. Neurons from both lines also showed an increased immobile fraction of endolysosomes present in the axon, whereas mobile organelles displayed shortened run distances in the retrograde direction. Overall, our results highlight the importance of maintaining the balance of tyrosinated and detyrosinated MTs for proper AIS length and axonal transport processes.
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Affiliation(s)
- Anja Konietzny
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
| | - Yuhao Han
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Centre for Structural Systems Biology, Hamburg 22607, Germany
- Structural Cell Biology of Viruses, Leibniz Institute of Virology (LIV), Hamburg 20251, Germany
| | - Yannes Popp
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Charité – Universitätsmedizin Berlin, Einstein Center for Neurosciences Berlin, 10117 Berlin, Germany
| | - Bas van Bommel
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Aditi Sharma
- University Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | | | - Nicolas Arbez
- Institut de Recherche Servier, Croissy 78290, France
| | - Marie-Jo Moutin
- University Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Leticia Peris
- University Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Marina Mikhaylova
- RG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin 10115, Germany
- Guest Group ‘Neuronal Protein Transport’, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
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2
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Sumi T, Harada K. Muscarinic acetylcholine receptor-dependent and NMDA receptor-dependent LTP and LTD share the common AMPAR trafficking pathway. iScience 2023; 26:106133. [PMID: 36866246 PMCID: PMC9972575 DOI: 10.1016/j.isci.2023.106133] [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: 06/20/2022] [Revised: 10/30/2022] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The forebrain cholinergic system promotes higher brain function in part by signaling through the M1 muscarinic acetylcholine receptor (mAChR). Long-term potentiation (LTP) and long-term depression (LTD) of excitatory synaptic transmission in the hippocampus are also induced by mAChR. An AMPA receptor (AMPAR) trafficking model for hippocampal neurons has been proposed to simulate N-methyl-D-aspartate receptor (NMDAR)-dependent synaptic plasticity in the early phase. In this study, we demonstrated the validity of the hypothesis that the mAChR-dependent LTP/LTD shares a common AMPAR trafficking pathway associated with NMDAR-dependent LTP/LTD. However, unlike NMDAR, Ca2+ influx into the spine cytosol occurs owing to the Ca2+ stored inside the ER and is induced via the activation of inositol 1,4,5-trisphosphate (IP3) receptors during M1 mAChR activation. Moreover, the AMPAR trafficking model implies that alterations in LTP and LTD observed in Alzheimer's disease could be attributed to age-dependent reductions in AMPAR expression levels.
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Affiliation(s)
- Tomonari Sumi
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
- Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
- Corresponding author
| | - Kouji Harada
- Department of Computer Science and Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan
- Center for IT-Based Education, Toyohashi University of Technology, Tempaku-cho, Toyohashi, 441-8580, Japan
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3
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Konietzny A, Grendel J, Kadek A, Bucher M, Han Y, Hertrich N, Dekkers DHW, Demmers JAA, Grünewald K, Uetrecht C, Mikhaylova M. Caldendrin and myosin V regulate synaptic spine apparatus localization via ER stabilization in dendritic spines. EMBO J 2022; 41:e106523. [PMID: 34935159 PMCID: PMC8844991 DOI: 10.15252/embj.2020106523] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/08/2021] [Accepted: 11/19/2021] [Indexed: 11/21/2022] Open
Abstract
Excitatory synapses of principal hippocampal neurons are frequently located on dendritic spines. The dynamic strengthening or weakening of individual inputs results in structural and molecular diversity of dendritic spines. Active spines with large calcium ion (Ca2+ ) transients are frequently invaded by a single protrusion from the endoplasmic reticulum (ER), which is dynamically transported into spines via the actin-based motor myosin V. An increase in synaptic strength correlates with stable anchoring of the ER, followed by the formation of an organelle referred to as the spine apparatus. Here, we show that myosin V binds the Ca2+ sensor caldendrin, a brain-specific homolog of the well-known myosin V interactor calmodulin. While calmodulin is an essential activator of myosin V motor function, we found that caldendrin acts as an inhibitor of processive myosin V movement. In mouse and rat hippocampal neurons, caldendrin regulates spine apparatus localization to a subset of dendritic spines through a myosin V-dependent pathway. We propose that caldendrin transforms myosin into a stationary F-actin tether that enables the localization of ER tubules and formation of the spine apparatus in dendritic spines.
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Affiliation(s)
- Anja Konietzny
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Jasper Grendel
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Alan Kadek
- Leibniz Institute for Experimental Virology (HPI)HamburgGermany
- European XFEL GmbHSchenefeldGermany
| | - Michael Bucher
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Yuhao Han
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
| | - Nathalie Hertrich
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | | | | | - Kay Grünewald
- Leibniz Institute for Experimental Virology (HPI)HamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Department of ChemistryUniversity of HamburgHamburgGermany
| | - Charlotte Uetrecht
- Leibniz Institute for Experimental Virology (HPI)HamburgGermany
- European XFEL GmbHSchenefeldGermany
- Centre for Structural Systems BiologyHamburgGermany
| | - Marina Mikhaylova
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
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4
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Bibeau JP, Galotto G, Wu M, Tüzel E, Vidali L. Quantitative cell biology of tip growth in moss. PLANT MOLECULAR BIOLOGY 2021; 107:227-244. [PMID: 33825083 PMCID: PMC8492783 DOI: 10.1007/s11103-021-01147-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/25/2021] [Indexed: 05/16/2023]
Abstract
KEY MESSAGE Here we review, from a quantitative point of view, the cell biology of protonemal tip growth in the model moss Physcomitrium patens. We focus on the role of the cytoskeleton, vesicle trafficking, and cell wall mechanics, including reviewing some of the existing mathematical models of tip growth. We provide a primer for existing cell biological tools that can be applied to the future study of tip growth in moss. Polarized cell growth is a ubiquitous process throughout the plant kingdom in which the cell elongates in a self-similar manner. This process is important for nutrient uptake by root hairs, fertilization by pollen, and gametophyte development by the protonemata of bryophytes and ferns. In this review, we will focus on the tip growth of moss cells, emphasizing the role of cytoskeletal organization, cytoplasmic zonation, vesicle trafficking, cell wall composition, and dynamics. We compare some of the existing knowledge on tip growth in protonemata against what is known in pollen tubes and root hairs, which are better-studied tip growing cells. To fully understand how plant cells grow requires that we deepen our knowledge in a variety of forms of plant cell growth. We focus this review on the model plant Physcomitrium patens, which uses tip growth as the dominant form of growth at its protonemal stage. Because mosses and vascular plants shared a common ancestor more than 450 million years ago, we anticipate that both similarities and differences between tip growing plant cells will provide mechanistic information of tip growth as well as of plant cell growth in general. Towards this mechanistic understanding, we will also review some of the existing mathematical models of plant tip growth and their applicability to investigate protonemal morphogenesis. We attempt to integrate the conclusions and data across cell biology and physical modeling to our current state of knowledge of polarized cell growth in P. patens and highlight future directions in the field.
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Affiliation(s)
- Jeffrey P Bibeau
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Giulia Galotto
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Min Wu
- Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, MA, USA
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Erkan Tüzel
- Bioengineering Department, Temple University, Philadelphia, PA, USA
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA.
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA.
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5
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Sumi T, Harada K. Mechanism underlying hippocampal long-term potentiation and depression based on competition between endocytosis and exocytosis of AMPA receptors. Sci Rep 2020; 10:14711. [PMID: 32895399 PMCID: PMC7477194 DOI: 10.1038/s41598-020-71528-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/17/2020] [Indexed: 02/08/2023] Open
Abstract
N-methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP) and long-term depression (LTD) of signal transmission form neural circuits and thus are thought to underlie learning and memory. These mechanisms are mediated by AMPA receptor (AMPAR) trafficking in postsynaptic neurons. However, the regulatory mechanism of bidirectional plasticity at excitatory synapses remains unclear. We present a network model of AMPAR trafficking for adult hippocampal pyramidal neurons, which reproduces both LTP and LTD. We show that the induction of both LTP and LTD is regulated by the competition between exocytosis and endocytosis of AMPARs, which are mediated by the calcium-sensors synaptotagmin 1/7 (Syt1/7) and protein interacting with C-kinase 1 (PICK1), respectively. Our result indicates that recycling endosomes containing AMPAR are always ready for Syt1/7-dependent exocytosis of AMPAR at peri-synaptic/synaptic membranes. This is because molecular motor myosin Vb constitutively transports the recycling endosome toward the membrane in a Ca2+-independent manner.
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Affiliation(s)
- Tomonari Sumi
- Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan. .,Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan.
| | - Kouji Harada
- Department of Computer Science and Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi, 441-8580, Japan
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6
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Cook AW, Gough RE, Toseland CP. Nuclear myosins - roles for molecular transporters and anchors. J Cell Sci 2020; 133:133/11/jcs242420. [PMID: 32499319 DOI: 10.1242/jcs.242420] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The myosin family of molecular motors are well-characterised cytoskeletal proteins. However, myosins are also present in the nucleus, where they have been shown to have roles in transcription, DNA repair and viral infections. Despite their involvement in these fundamental cellular processes, our understanding of these functions and their regulation remains limited. Recently, research on nuclear myosins has been gathering pace, and this Review will evaluate the current state of the field. Here, we will focus on the variation in structure of nuclear myosins, their nuclear import and their roles within transcription, DNA damage, chromatin organisation and viral infections. We will also consider both the biochemical and biophysical properties and restraints that are placed on these multifunctional motors, and how they link to their cytoplasmic counterparts. By highlighting these properties and processes, we show just how integral nuclear myosins are for cellular survival.
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Affiliation(s)
- Alexander W Cook
- Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
| | - Rosemarie E Gough
- Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
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Liu W, Tang Q, Jin J, Zhu T, Dai Y, Shi Y. Sex differences in cardiovascular risk factors for myocardial infarction. Herz 2020; 46:115-122. [PMID: 32377778 DOI: 10.1007/s00059-020-04911-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/23/2020] [Accepted: 02/27/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND Cardiovascular disease is a leading cause of mortality worldwide. This study investigated the effects of sex on traditional cardiovascular risk factors for remote myocardial infarction in a community. METHODS A cross-sectional study was performed comprising 20,899 participants who underwent physical examination from 2013 to 2015, including systemic blood pressure and 12-lead electrocardiogram monitoring. Fasting blood samples were collected for blood cell counts and biochemistry tests. Remote myocardial infarction was diagnosed on the basis of electrocardiogram findings. RESULTS A total of 71 male and 21 female patients aged over 50 years were identified with remote myocardial infarction. In the female cohort, low-density lipoprotein (LDL), total cholesterol (TC), as well as high-density lipoprotein (HDL) were negatively correlated with myocardial infarction after adjusting for age. In the male cohort, after adjusting for age, serum levels of glycated hemoglobin (HbA1c) and fasting glucose were positively correlated with myocardial infarction, but the lipid profile, including low-density lipoprotein (LDL), total cholesterol (TC), and high-density lipoprotein (HDL), was negatively correlated with remote myocardial infarction. CONCLUSION In the male population, dyslipidemia and abnormal glucose metabolism play a role in myocardial infarction. In the female population, dyslipidemia is independent of glucose metabolism. This study highlights sex differences in the regulation of lipids and glucose metabolism in patients with remote myocardial infarction.
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Affiliation(s)
- Wenjie Liu
- Biomedical Research Center, Zhongshan Hospital Fudan University, Fenglin Road 180, CN-200032, Shanghai, China
| | - Qunye Tang
- Shanghai Key Laboratory of Transplantation, Zhongshan Hospital Fudan University, Shanghai, China
- Department of Urology, Zhongshan Hospital Fudan University, Shanghai, China
| | - Jiangjun Jin
- Biomedical Research Center, Zhongshan Hospital Fudan University, Fenglin Road 180, CN-200032, Shanghai, China
| | - Tongyu Zhu
- Shanghai Key Laboratory of Transplantation, Zhongshan Hospital Fudan University, Shanghai, China
- Department of Urology, Zhongshan Hospital Fudan University, Shanghai, China
| | - Yi Dai
- The Hospital Office, Tongji Hospital Branch, Tongji University, Chifeng Road 50, CN-200092, Shanghai, China.
| | - Yi Shi
- Biomedical Research Center, Zhongshan Hospital Fudan University, Fenglin Road 180, CN-200032, Shanghai, China.
- Shanghai Key Laboratory of Transplantation, Zhongshan Hospital Fudan University, Shanghai, China.
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8
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Zhang N, Yao LL, Li XD. Regulation of class V myosin. Cell Mol Life Sci 2018; 75:261-273. [PMID: 28730277 PMCID: PMC11105390 DOI: 10.1007/s00018-017-2599-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/27/2017] [Accepted: 07/17/2017] [Indexed: 01/26/2023]
Abstract
Class V myosin (myosin-5) is a molecular motor that functions as an organelle transporter. The activation of myosin-5's motor function has long been known to be associated with a transition from the folded conformation in the off-state to the extended conformation in the on-state, but only recently have we begun to understand the underlying mechanism. The globular tail domain (GTD) of myosin-5 has been identified as the inhibitory domain and has recently been shown to function as a dimer in regulating the motor function. The folded off-state of myosin-5 is stabilized by multiple intramolecular interactions, including head-GTD interactions, GTD-GTD interactions, and interactions between the GTD and the C-terminus of the first coiled-coil segment. Any cellular factor that affects these intramolecular interactions and thus the stability of the folded conformation of myosin-5 would be expected to regulate myosin-5 motor function. Both the adaptor proteins of myosin-5 and Ca2+ are potential regulators of myosin-5 motor function, because they can destabilize its folded conformation. A combination of these regulators provides a versatile scheme in regulating myosin-5 motor function in the cell.
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Affiliation(s)
- Ning Zhang
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lin-Lin Yao
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiang-Dong Li
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Masters TA, Kendrick-Jones J, Buss F. Myosins: Domain Organisation, Motor Properties, Physiological Roles and Cellular Functions. Handb Exp Pharmacol 2017; 235:77-122. [PMID: 27757761 DOI: 10.1007/164_2016_29] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Myosins are cytoskeletal motor proteins that use energy derived from ATP hydrolysis to generate force and movement along actin filaments. Humans express 38 myosin genes belonging to 12 classes that participate in a diverse range of crucial activities, including muscle contraction, intracellular trafficking, cell division, motility, actin cytoskeletal organisation and cell signalling. Myosin malfunction has been implicated a variety of disorders including deafness, hypertrophic cardiomyopathy, Usher syndrome, Griscelli syndrome and cancer. In this chapter, we will first discuss the key structural and kinetic features that are conserved across the myosin family. Thereafter, we summarise for each member in turn its unique functional and structural adaptations, cellular roles and associated pathologies. Finally, we address the broad therapeutic potential for pharmacological interventions that target myosin family members.
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Affiliation(s)
- Thomas A Masters
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| | | | - Folma Buss
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
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Calmodulin in complex with the first IQ motif of myosin-5a functions as an intact calcium sensor. Proc Natl Acad Sci U S A 2016; 113:E5812-E5820. [PMID: 27647889 DOI: 10.1073/pnas.1607702113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The motor function of vertebrate myosin-5a is inhibited by its tail in a Ca2+-dependent manner. We previously demonstrated that the calmodulin (CaM) bound to the first isoleucine-glutamine (IQ) motif (IQ1) of myosin-5a is responsible for the Ca2+-dependent regulation of myosin-5a. We have solved the crystal structure of a truncated myosin-5a containing the motor domain and IQ1 (MD-IQ1) complexed with Ca2+-bound CaM (Ca2+-CaM) at 2.5-Å resolution. Compared with the structure of the MD-IQ1 complexed with essential light chain (an equivalent of apo-CaM), MD-IQ1/Ca2+-CaM displays large conformational differences in IQ1/CaM and little difference in the motor domain. In the MD-IQ1/Ca2+-CaM structure, the N-lobe and the C-lobe of Ca2+-CaM adopt an open conformation and grip the C-terminal and the N-terminal portions of the IQ1, respectively. Remarkably, the interlobe linker of CaM in IQ1/Ca2+-CaM is in a position opposite that in IQ1/apo-CaM, suggesting that CaM flip-flops relative to the IQ1 during the Ca2+ transition. We demonstrated that CaM continuously associates with the IQ1 during the Ca2+ transition and that the binding of CaM to IQ1 increases Ca2+ affinity and substantially changes the kinetics of the Ca2+ transition, suggesting that the IQ1/CaM complex functions as an intact Ca2+ sensor responding to distinct calcium signals.
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Melanophilin Stimulates Myosin-5a Motor Function by Allosterically Inhibiting the Interaction between the Head and Tail of Myosin-5a. Sci Rep 2015; 5:10874. [PMID: 26039755 PMCID: PMC4454200 DOI: 10.1038/srep10874] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/05/2015] [Indexed: 11/18/2022] Open
Abstract
The tail-inhibition model is generally accepted for the regulation of myosin-5a motor function. Inhibited myosin-5a is in a folded conformation in which its globular tail domain (GTD) interacts with its head and inhibits its motor function, and high Ca2+ or cargo binding may reduce the interaction between the GTD and the head of myosin-5a, thus activating motor activity. Although it is well established that myosin-5a motor function is regulated by Ca2+, little is known about the effects of cargo binding. We previously reported that melanophilin (Mlph), a myosin-5a cargo-binding protein, is capable of activating myosin-5a motor function. Here, we report that Mlph-GTBDP, a 26 amino-acid-long peptide of Mlph, is sufficient for activating myosin-5a motor function. We demonstrate that Mlph-GTBDP abolishes the interaction between the head and GTD of myosin-5a, thereby inducing a folded-to-extended conformation transition for myosin-5a and activating its motor function. Mutagenesis of the GTD shows that the GTD uses two distinct, non-overlapping regions to interact with Mlph-GTBDP and the head of myosin-5a. We propose that the GTD is an allosteric protein and that Mlph allosterically inhibits the interaction between the GTD and head of myosin-5a, thereby activating myosin-5a motor function.
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12
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The motor function of Drosophila melanogaster myosin-5 is activated by calcium and cargo-binding protein dRab11. Biochem J 2015; 469:135-44. [PMID: 25940004 DOI: 10.1042/bj20141330] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 05/05/2015] [Indexed: 12/14/2022]
Abstract
In the Drosophila melanogaster compound eye, myosin-5 (DmM5) plays two distinct roles in response to light stimulation: transport of pigment granules to the rhabdomere base to decrease light exposure and transport of rhodopsin-bearing vesicles to the rhabdomere base to compensate for the rhodopsin loss during light exposure. However, little is known of how the motor function of DmM5 is regulated at the molecular level. In the present study, we overexpressed DmM5 in Sf9 insect cells and investigated its regulation using purified proteins. We found that the actin-activated ATPase activity of DmM5 is significantly lower than that of the truncated DmM5 having the C-terminal globular tail domain (GTD) deleted, indicating that the GTD is the inhibitory domain. The actin-activated ATPase activity of DmM5 is significantly activated by micromolar levels of calcium. DmM5 associates with pigment granules and rhodopsin-bearing vesicles through cargo-binding proteins Lightoid (Ltd) and dRab11 respectively. We found that GTP-bound dRab11, but not Ltd, significantly activates DmM5 actin-activated ATPase activity. Moreover, we identified Gln(1689) in the GTD as the critical residue for the interaction with dRab11 and activation of DmM5 motor function by dRab11. Based on those results, we propose that DmM5-dependent transport of pigment granules is directly activated by light-induced calcium influx and the DmM5-dependent transport of rhodopsin-bearing vesicle is activated by active GTP-bound dRab11, whose formation is stimulated by light-induced calcium influx.
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13
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Lu Z, Ma XN, Zhang HM, Ji HH, Ding H, Zhang J, Luo D, Sun Y, Li XD. Mouse myosin-19 is a plus-end-directed, high-duty ratio molecular motor. J Biol Chem 2014; 289:18535-48. [PMID: 24825904 DOI: 10.1074/jbc.m114.569087] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Class XIX myosin (Myo19) is a vertebrate-specific unconventional myosin, responsible for the transport of mitochondria. To characterize biochemical properties of Myo19, we prepared recombinant mouse Myo19-truncated constructs containing the motor domain and the IQ motifs using the baculovirus/Sf9 expression system. We identified regulatory light chain (RLC) of smooth muscle/non-muscle myosin-2 as the light chain of Myo19. The actin-activated ATPase activity and the actin-gliding velocity of Myo19-truncated constructs were about one-third and one-sixth as those of myosin-5a, respectively. The apparent affinity of Myo19 to actin was about the same as that of myosin-5a. The RLCs bound to Myo19 could be phosphorylated by myosin light chain kinase, but this phosphorylation had little effect on the actin-activated ATPase activity and the actin-gliding activity of Myo19-truncated constructs. Using dual fluorescence-labeled actin filaments, we determined that Myo19 is a plus-end-directed molecular motor. We found that, similar to that of the high-duty ratio myosin, such as myosin-5a, ADP release rate was comparable with the maximal actin-activated ATPase activity of Myo19, indicating that ADP release is a rate-limiting step for the ATPase cycle of acto-Myo19. ADP strongly inhibited the actin-activated ATPase activity and actin-gliding activity of Myo19-truncated constructs. Based on the above results, we concluded that Myo19 is a high-duty ratio molecular motor moving to the plus-end of the actin filament.
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Affiliation(s)
- Zekuan Lu
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
| | - Xiao-Nan Ma
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
| | - Hai-Man Zhang
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
| | - Huan-Hong Ji
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
| | - Hao Ding
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
| | - Jie Zhang
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
| | - Dan Luo
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
| | - Yujie Sun
- the Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiang-Dong Li
- From the Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 and
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14
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Haraguchi T, Tominaga M, Matsumoto R, Sato K, Nakano A, Yamamoto K, Ito K. Molecular characterization and subcellular localization of Arabidopsis class VIII myosin, ATM1. J Biol Chem 2014; 289:12343-55. [PMID: 24637024 PMCID: PMC4007431 DOI: 10.1074/jbc.m113.521716] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/12/2014] [Indexed: 02/02/2023] Open
Abstract
Land plants possess myosin classes VIII and XI. Although some information is available on the molecular properties of class XI myosins, class VIII myosins are not characterized. Here, we report the first analysis of the enzymatic properties of class VIII myosin. The motor domain of Arabidopsis class VIII myosin, ATM1 (ATM1-MD), and the motor domain plus one IQ motif (ATM1-1IQ) were expressed in a baculovirus system and characterized. ATM1-MD and ATM1-1IQ had low actin-activated Mg(2+)-ATPase activity (Vmax = 4 s(-1)), although their affinities for actin were high (Kactin = 4 μM). The actin-sliding velocities of ATM1-MD and ATM1-1IQ were 0.02 and 0.089 μm/s, respectively, from which the value for full-length ATM1 is calculated to be ∼0.2 μm/s. The results of actin co-sedimentation assay showed that the duty ratio of ATM1 was ∼90%. ADP dissociation from the actin·ATM1 complex (acto-ATM1) was extremely slow, which accounts for the low actin-sliding velocity, low actin-activated ATPase activity, and high duty ratio. The rate of ADP dissociation from acto-ATM1 was markedly biphasic with fast and slow phase rates (5.1 and 0.41 s(-1), respectively). Physiological concentrations of free Mg(2+) modulated actin-sliding velocity and actin-activated ATPase activity by changing the rate of ADP dissociation from acto-ATM1. GFP-fused full-length ATM1 expressed in Arabidopsis was localized to plasmodesmata, plastids, newly formed cell walls, and actin filaments at the cell cortex. Our results suggest that ATM1 functions as a tension sensor/generator at the cell cortex and other structures in Arabidopsis.
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Affiliation(s)
- Takeshi Haraguchi
- From the Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522
| | - Motoki Tominaga
- the Live Cell Molecular Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198
- the Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, and
| | - Rie Matsumoto
- From the Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522
| | - Kei Sato
- the Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Akihiko Nakano
- the Live Cell Molecular Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198
- the Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Keiichi Yamamoto
- From the Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522
| | - Kohji Ito
- From the Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522
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15
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Haraguchi T, Honda K, Wanikawa Y, Shoji N, Yamamoto K, Ito K. Function of the head-tail junction in the activity of myosin II. Biochem Biophys Res Commun 2013; 440:490-4. [PMID: 24041685 DOI: 10.1016/j.bbrc.2013.09.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 09/06/2013] [Indexed: 10/26/2022]
Abstract
All class II myosins have the conserved amino acid sequence Pro-Leu-Leu at their head-tail junctions. We systematically altered this sequence in smooth muscle heavy meromyosin (HMM) by site-directed mutagenesis and examined the effects of these mutations on actin-myosin interactions. Deletion of the proline and second leucine did not cause any noticeable change in either actin-activated ATPase activity or actin-sliding velocity. In contrast, deletion of the two leucine residues and substitution of the first leucine with alanine resulted in a 14-fold and 5-fold decrease, respectively, in actin-activated ATPase activity. However, both these mutations did not appreciably affect actin-sliding velocity, which was consistent with a result that there was no considerable change in the ADP release rate from acto-HMM in the deletion mutant. In contrast to double-headed HMM, a single-headed subfragment-1 (S1) with a Leu-Leu deletion mutation exhibited actin activated ATPase activity similar to that by wild type S1. Our results suggest that the first leucine of the conserved Leu-Leu sequence at the head-tail junction profoundly affects the cooperativity between the two heads involved in the actin activated ATPase activity of myosin II.
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Affiliation(s)
- Takeshi Haraguchi
- Department of Biology, Graduate School of Science, Chiba University, Inage-ku, Chiba 263-8522, Japan
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16
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Elias S, Delestre C, Ory S, Marais S, Courel M, Vazquez-Martinez R, Bernard S, Coquet L, Malagon MM, Driouich A, Chan P, Gasman S, Anouar Y, Montero-Hadjadje M. Chromogranin A induces the biogenesis of granules with calcium- and actin-dependent dynamics and exocytosis in constitutively secreting cells. Endocrinology 2012; 153:4444-56. [PMID: 22851679 DOI: 10.1210/en.2012-1436] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chromogranins are a family of acidic glycoproteins that play an active role in hormone and neuropeptide secretion through their crucial role in secretory granule biogenesis in neuroendocrine cells. However, the molecular mechanisms underlying their granulogenic activity are still not fully understood. Because we previously demonstrated that the expression of the major component of secretory granules, chromogranin A (CgA), is able to induce the formation of secretory granules in nonendocrine COS-7 cells, we decided to use this model to dissect the mechanisms triggered by CgA leading to the biogenesis and trafficking of such granules. Using quantitative live cell imaging, we first show that CgA-induced organelles exhibit a Ca(2+)-dependent trafficking, in contrast to native vesicle stomatitis virus G protein-containing constitutive vesicles. To identify the proteins that confer such properties to the newly formed granules, we developed CgA-stably-expressing COS-7 cells, purified their CgA-containing granules by subcellular fractionation, and analyzed the granule proteome by liquid chromatography-tandem mass spectrometry. This analysis revealed the association of several cytosolic proteins to the granule membrane, including GTPases, cytoskeleton-based molecular motors, and other proteins with actin- and/or Ca(2+)-binding properties. Furthermore, disruption of cytoskeleton affects not only the distribution and the transport but also the Ca(2+)-evoked exocytosis of the CgA-containing granules, indicating that these granules interact with microtubules and cortical actin for the regulated release of their content. These data demonstrate for the first time that the neuroendocrine factor CgA induces the recruitment of cytoskeleton-, GTP-, and Ca(2+)-binding proteins in constitutively secreting COS-7 cells to generate vesicles endowed with typical dynamics and exocytotic properties of neuroendocrine secretory granules.
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Affiliation(s)
- Salah Elias
- Institut National de la Santé et de la Recherche Médicale (Inserm) U982, University of Rouen, Mont-Saint-Aignan 76821, France
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17
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Tominaga M, Kojima H, Yokota E, Nakamori R, Anson M, Shimmen T, Oiwa K. Calcium-induced mechanical change in the neck domain alters the activity of plant myosin XI. J Biol Chem 2012; 287:30711-8. [PMID: 22740687 PMCID: PMC3436315 DOI: 10.1074/jbc.m112.346668] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 06/19/2012] [Indexed: 11/25/2022] Open
Abstract
Plant myosin XI functions as a motor that generates cytoplasmic streaming in plant cells. Although cytoplasmic streaming is known to be regulated by intracellular Ca(2+) concentration, the molecular mechanism underlying this control is not fully understood. Here, we investigated the mechanism of regulation of myosin XI by Ca(2+) at the molecular level. Actin filaments were easily detached from myosin XI in an in vitro motility assay at high Ca(2+) concentration (pCa 4) concomitant with the detachment of calmodulin light chains from the neck domains. Electron microscopic observations showed that myosin XI at pCa 4 shortened the neck domain by 30%. Single-molecule analysis revealed that the step size of myosin XI at pCa 4 was shortened to 27 nm under low load and to 22 nm under high load compared with 35 nm independent of the load for intact myosin XI. These results indicate that modulation of the mechanical properties of the neck domain is a key factor for achieving the Ca(2+)-induced regulation of cytoplasmic streaming.
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Affiliation(s)
- Motoki Tominaga
- From the Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Hiroaki Kojima
- From the Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Etsuo Yokota
- the Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo 678-1297, Japan, and
| | - Rinna Nakamori
- From the Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Michael Anson
- the Division of Physical Biochemistry, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
| | - Teruo Shimmen
- the Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo 678-1297, Japan, and
| | - Kazuhiro Oiwa
- From the Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
- the Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo 678-1297, Japan, and
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18
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Lu Z, Shen M, Cao Y, Zhang HM, Yao LL, Li XD. Calmodulin bound to the first IQ motif is responsible for calcium-dependent regulation of myosin 5a. J Biol Chem 2012; 287:16530-40. [PMID: 22437832 DOI: 10.1074/jbc.m112.343079] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin 5a is as yet the best-characterized unconventional myosin motor involved in transport of organelles along actin filaments. It is well-established that myosin 5a is regulated by its tail in a Ca(2+)-dependent manner. The fact that the actin-activated ATPase activity of myosin 5a is stimulated by micromolar concentrations of Ca(2+) and that calmodulin (CaM) binds to IQ motifs of the myosin 5a heavy chain indicates that Ca(2+) regulates myosin 5a function via bound CaM. However, it is not known which IQ motif and bound CaM are responsible for the Ca(2+)-dependent regulation and how the head-tail interaction is affected by Ca(2+). Here, we found that the CaM in the first IQ motif (IQ1) is responsible for Ca(2+) regulation of myosin 5a. In addition, we demonstrate that the C-lobe fragment of CaM in IQ1 is necessary for mediating Ca(2+) regulation of myosin 5a, suggesting that the C-lobe fragment of CaM in IQ1 participates in the interaction between the head and the tail. We propose that Ca(2+) induces a conformational change of the C-lobe of CaM in IQ1 and prevents interaction between the head and the tail, thus activating motor function.
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Affiliation(s)
- Zekuan Lu
- Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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19
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Single-molecule stepping and structural dynamics of myosin X. Nat Struct Mol Biol 2010; 17:485-91. [PMID: 20364131 DOI: 10.1038/nsmb.1785] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 02/03/2010] [Indexed: 11/08/2022]
Abstract
Myosin X is an unconventional myosin with puzzling motility properties. We studied the motility of dimerized myosin X using the single-molecule fluorescence techniques polTIRF, FIONA and Parallax to measure the rotation angles and three-dimensional position of the molecule during its walk. It was found that Myosin X steps processively in a hand-over-hand manner following a left-handed helical path along both single actin filaments and bundles. Its step size and velocity are smaller on actin bundles than individual filaments, suggesting myosin X often steps onto neighboring filaments in a bundle. The data suggest that a previously postulated single alpha-helical domain mechanically extends the lever arm, which has three IQ motifs, and either the neck-tail hinge or the tail is flexible. These structural features, in conjunction with the membrane- and microtubule-binding domains, enable myosin X to perform multiple functions on varied actin structures in cells.
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20
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Kögel T, Rudolf R, Hodneland E, Hellwig A, Kuznetsov SA, Seiler F, Söllner TH, Barroso J, Gerdes HH. Distinct Roles of Myosin Va in Membrane Remodeling and Exocytosis of Secretory Granules. Traffic 2010; 11:637-50. [DOI: 10.1111/j.1600-0854.2010.01048.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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21
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A novel allele of myosin VIIa reveals a critical function for the C-terminal FERM domain for melanosome transport in retinal pigment epithelial cells. J Neurosci 2010; 29:15810-8. [PMID: 20016096 DOI: 10.1523/jneurosci.4876-09.2009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mutations in the head and tail domains of the motor protein myosin VIIA (MYO7A) cause deaf-blindness (Usher syndrome type 1B, USH1B) and nonsyndromic deafness (DFNB2, DFNA11). The head domain binds to F-actin and serves as the MYO7A motor domain, but little is known about the function of the tail domain. In a genetic screen, we have identified polka mice, which carry a mutation (c.5742 + 5G > A) that affects splicing of the MYO7A transcript and truncates the MYO7A tail domain at the C-terminal FERM domain. In the inner ear, expression of the truncated MYO7A protein is severely reduced, leading to defects in hair cell development. In retinal pigment epithelial (RPE) cells, the truncated MYO7A protein is expressed at comparative levels to wild-type protein but fails to associate with and transport melanosomes. We conclude that the C-terminal FERM domain of MYO7A is critical for melanosome transport in RPE cells. Our findings also suggest that MYO7A mutations can lead to tissue-specific effects on protein levels, which may explain why some mutations in MYO7A lead to deafness without retinal impairment.
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22
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Sugimoto Y, Sato O, Watanabe S, Ikebe R, Ikebe M, Wakabayashi K. Reverse conformational changes of the light chain-binding domain of myosin V and VI processive motor heads during and after hydrolysis of ATP by small-angle X-ray solution scattering. J Mol Biol 2009; 392:420-35. [PMID: 19607837 DOI: 10.1016/j.jmb.2009.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 07/04/2009] [Accepted: 07/07/2009] [Indexed: 11/19/2022]
Abstract
We used small-angle X-ray solution scattering (SAXS) technique to investigate the nucleotide-mediated conformational changes of the head domains [subfragment 1 (S1)] of myosin V and VI processive motors that govern their directional preference for motility on actin. Recombinant myosin V-S1 with two IQ motifs (MV-S1IQ2) and myosin VI-S1 (MVI-S1) were engineered from Sf9 cells using a baculovirus expression system. The radii of gyration (R(g)) of nucleotide-free MV-S1IQ2 and MVI-S1 were 48.6 and 48.8 A, respectively. In the presence of ATP, the R(g) value of MV-S1IQ2 decreased to 46.7 A, while that of MVI-S1 increased to 51.7 A, and the maximum chord length of the molecule decreased by ca 9% for MV-S1IQ2 and increased by ca 6% for MVI-S1. These opposite directional changes were consistent with those occurring in S1s with ADP and Vi or AlF(4)(-2) bound (i.e., in states mimicking the ADP/Pi-bound state of ATP hydrolysis). Binding of AMPPNP induced R(g) changes of both constructs similar to those in the presence of ATP, suggesting that the timing of the structural changes for their motion on actin is upon binding of ATP (the pre-hydrolysis state) during the ATPase cycle. Binding of ADP to MV-S1IQ2 and MVI-S1 caused their R(g) values to drop below those in the nucleotide-free state. Thus, upon the release of Pi, the reverse conformational change could occur, coupling to drive the directional motion on actin. The amount of R(g) change upon the release of Pi was ca 6.4 times greater in MVI-S1 than in MV-S1IQ2, relating to the production of the large stroke of the MVI motor during its translocation on actin. Atomic structural models for these S1s based upon the ab initio shape reconstruction from X-ray scattering data were constructed, showing that MVI-S1 has the light-chain-binding domain positioned in the opposite direction to MV-S1IQ2 in both the pre- and post-powerstroke transition. The angular change between the light chain-binding domains of MV-S1IQ2 in the pre- to post-powerstroke transition was approximately 50 degrees, comparable to that of MII-S1. On the other hand, that of MVI-S1 was approximately 100 degrees or approximately 130 degrees much less than the currently postulated changes to allow the maximal stroke size of myosin VI-S1 but still significantly larger than those of other myosins reported so far. The results suggest that some additional alterations or elements are required for MVI-S1 to take maximal working strokes along the actin filament.
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Affiliation(s)
- Yasunobu Sugimoto
- Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
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23
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The tail binds to the head-neck domain, inhibiting ATPase activity of myosin VIIA. Proc Natl Acad Sci U S A 2009; 106:8483-8. [PMID: 19423668 DOI: 10.1073/pnas.0812930106] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosin VIIA is an unconventional myosin, responsible for human Usher syndrome type 1B, which causes hearing and visual loss. Here, we studied the molecular mechanism of regulation of myosin VIIA, which is currently unknown. Although it was originally thought that myosin VIIA is a dimeric myosin, our electron microscopic (EM) observations revealed that full-length Drosophila myosin VIIA (DM7A) is a monomer. Interestingly, the tail domain markedly inhibits the actin-activated ATPase activity of tailless DM7A at low Ca(2+) but not high Ca(2+). By examining various deletion constructs, we found that deletion of the distal IQ domain, the C-terminal region of the tail, and the N-terminal region of the tail abolishes the tail-induced inhibition of ATPase activity. Single-particle EM analysis of full-length DM7A at low Ca(2+) suggests that the tail folds back on to the head, where it contacts both the motor core domain and the neck domain, forming an inhibited conformation. We concluded that unconventional myosin that may be present a monomer in the cell can be regulated by intramolecular interaction of the tail with the head.
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24
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Wang X, Schwarz TL. The mechanism of Ca2+ -dependent regulation of kinesin-mediated mitochondrial motility. Cell 2009; 136:163-74. [PMID: 19135897 DOI: 10.1016/j.cell.2008.11.046] [Citation(s) in RCA: 659] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 10/14/2008] [Accepted: 11/24/2008] [Indexed: 01/05/2023]
Abstract
Mitochondria are mobile organelles and cells regulate mitochondrial movement in order to meet the changing energy needs of each cellular region. Ca(2+) signaling, which halts both anterograde and retrograde mitochondrial motion, serves as one regulatory input. Anterograde mitochondrial movement is generated by kinesin-1, which interacts with the mitochondrial protein Miro through an adaptor protein, milton. We show that kinesin is present on all axonal mitochondria, including those that are stationary or moving retrograde. We also show that the EF-hand motifs of Miro mediate Ca(2+)-dependent arrest of mitochondria and elucidate the regulatory mechanism. Rather than dissociating kinesin-1 from mitochondria, Ca(2+)-binding permits Miro to interact directly with the motor domain of kinesin-1, preventing motor/microtubule interactions. Thus, kinesin-1 switches from an active state in which it is bound to Miro only via milton, to an inactive state in which direct binding to Miro prevents its interaction with microtubules. Disrupting Ca(2+)-dependent regulation diminishes neuronal resistance to excitotoxicity.
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Affiliation(s)
- Xinnan Wang
- F.M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, MA 02115, USA
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25
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Higashi-Fujime S, Nakamura A. Cell and molecular biology of the fastest myosins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 276:301-47. [PMID: 19584016 DOI: 10.1016/s1937-6448(09)76007-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Chara myosin is a class XI plant myosin in green algae Chara corallina and responsible for fast cytoplasmic streaming. The Chara myosin exhibits the fastest sliding movement of F-actin at 60 mum/s as observed so far, 10-fold of the shortening speed of muscle. It has some distinct properties differing from those of muscle myosin. Although knowledge about Chara myosin is very limited at present, we have tried to elucidate functional bases of its characteristics by comparing with those of other myosins. In particular, we have built the putative atomic model of Chara myosin by using the homology-based modeling system and databases. Based on the putative structure of Chara myosin obtained, we have analyzed the relationship between structure and function of Chara myosin to understand its distinct properties from various aspects by referring to the accumulated knowledge on mechanochemical and structural properties of other classes of myosin, particularly animal and fungal myosin V. We will also discuss the functional significance of Chara myosin in a living cell.
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Affiliation(s)
- Sugie Higashi-Fujime
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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26
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Bennett RD, Caride AJ, Mauer AS, Strehler EE. Interaction with the IQ3 motif of myosin-10 is required for calmodulin-like protein-dependent filopodial extension. FEBS Lett 2008; 582:2377-81. [DOI: 10.1016/j.febslet.2008.05.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 04/25/2008] [Accepted: 05/20/2008] [Indexed: 10/21/2022]
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27
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Folding and regulation in myosins II and V. J Muscle Res Cell Motil 2008; 28:363-70. [PMID: 18427938 DOI: 10.1007/s10974-008-9134-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Accepted: 03/04/2008] [Indexed: 10/22/2022]
Abstract
The enzymatic activity of many myosins is regulated by various means including calcium binding, phosphorylation or binding of receptor molecules. In this review we compare and contrast the regulation of smooth muscle myosin II and myosin Va with particular emphasis on the structural basis for the regulation. Both myosins adopt folded compact conformations in their off states, but the details of the conformations are markedly different. In the regulated smooth muscle myosin II, the key feature is an asymmetric interaction between the two heads of the molecule with contributions of specific tail-head interactions. In myosin V the key feature is an interaction between the heads and the globular tail domain.
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28
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The globular tail domain puts on the brake to stop the ATPase cycle of myosin Va. Proc Natl Acad Sci U S A 2008; 105:1140-5. [PMID: 18216256 DOI: 10.1073/pnas.0709741105] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosin Va is a well known processive motor involved in transport of organelles. A tail-inhibition model is generally accepted for the regulation of myosin Va: inhibited myosin Va is in a folded conformation such that the tail domain interacts with and inhibits myosin Va motor activity. Recent studies indicate that it is the C-terminal globular tail domain (GTD) that directly inhibits the motor activity of myosin Va. In the present study, we identified a conserved acidic residue in the motor domain (Asp-136) and two conserved basic residues in the GTD (Lys-1706 and Lys-1779) as critical residues for this regulation. Alanine mutations of these conserved charged residues not only abolished the inhibition of motor activity by the GTD but also prevented myosin Va from forming a folded conformation. We propose that Asp-136 forms ionic interactions with Lys-1706 and Lys-1779. This assignment locates the GTD-binding site in a pocket of the motor domain, formed by the N-terminal domain, converter, and the calmodulin in the first IQ motif. We propose that binding of the GTD to the motor domain prevents the movement of the converter/lever arm during ATP hydrolysis cycle, thus inhibiting the chemical cycle of the motor domain.
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29
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Ikebe M. Regulation of the function of mammalian myosin and its conformational change. Biochem Biophys Res Commun 2008; 369:157-64. [PMID: 18211803 DOI: 10.1016/j.bbrc.2008.01.057] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 01/03/2008] [Indexed: 12/01/2022]
Abstract
It has been known that the phosphorylation of the regulatory light chain, residing at the head/rod junction of the molecule activates the motor activity of smooth muscle and non-muscle conventional myosin (myosin II), and triggers a large conformational change of the molecule from the inhibited folded conformation to the active extended conformation. Recent structural analysis has revealed the structural basis of the inhibition of the motor function of the two heads in the inhibited conformation. On the other hand, recent studies have revealed that a processive unconventional myosin, myosin V, also shows a large change in the conformation from the folded to an extended form and this explains the activation mechanism of myosin V motor activity. These findings suggest the presence of a common scenario for the regulation of motor protein functions.
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Affiliation(s)
- Mitsuo Ikebe
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
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30
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Takagi Y, Yang Y, Fujiwara I, Jacobs D, Cheney RE, Sellers JR, Kovács M. Human myosin Vc is a low duty ratio, nonprocessive molecular motor. J Biol Chem 2008; 283:8527-37. [PMID: 18201966 DOI: 10.1074/jbc.m709150200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin Vc is the product of one of the three genes of the class V myosin found in vertebrates. It is widely found in secretory and glandular tissues, with a possible involvement in transferrin trafficking. Transient and steady-state kinetic studies of human myosin Vc were performed using a truncated, single-headed construct. Steady-state actin-activated ATPase measurements revealed a V(max) of 1.8 +/- 0.3 s(-1) and a K(ATPase) of 43 +/- 11 microm. Unlike previously studied vertebrate myosin Vs, the rate-limiting step in the actomyosin Vc ATPase pathway is the release of inorganic phosphate (~1.5 s(-1)), rather than the ADP release step (~12.0-16.0 s(-1)). Nevertheless, the ADP affinity of actomyosin Vc (K(d) = 0.25 +/- 0.02 microm) reflects a higher ADP affinity than seen in other myosin V isoforms. Using the measured kinetic rates, the calculated duty ratio of myosin Vc was approximately 10%, indicating that myosin Vc spends the majority of the actomyosin ATPase cycle in weak actin-binding states, unlike the other vertebrate myosin V isoforms. Consistent with this, a fluorescently labeled double-headed heavy meromyosin form showed no processive movements along actin filaments in a single molecule assay, but it did move actin filaments at a velocity of approximately 24 nm/s in ensemble assays. Kinetic simulations reveal that the high ADP affinity of actomyosin Vc may lead to elevations of the duty ratio of myosin Vc to as high as 64% under possible physiological ADP concentrations. This, in turn, may possibly imply a regulatory mechanism that may be sensitive to moderate changes in ADP concentration.
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Affiliation(s)
- Yasuharu Takagi
- Laboratory of Molecular Physiology, NHLBI, NIH, Bethesda, MD 20892-8015, USA
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31
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Komatsu S, Ikebe M. The phosphorylation of myosin II at the Ser1 and Ser2 is critical for normal platelet-derived growth factor induced reorganization of myosin filaments. Mol Biol Cell 2007; 18:5081-90. [PMID: 17928407 DOI: 10.1091/mbc.e06-12-1076] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phosphorylation of the regulatory light chain of myosin II (MLC(20)) at the activation sites promotes both the motor activity and the filament formation of myosin II, thus playing an important role in various cell motile processes. In contrast, the physiological function of phosphorylation of MLC(20) at the inhibitory sites is unknown. Here we report for the first time the function of the inhibitory site phosphorylation in the cells. We successfully produced the antibodies specifically recognizing the phosphorylation sites of MLC(20) at Ser1, and the platelet-derived growth factor (PDGF)-induced change in the phosphorylation at the Ser1 was monitored. The phosphorylation of MLC(20) at the Ser1 significantly increased during the PDGF-induced actin cytoskeletal reorganization. PDGF disassembled the stress fibers, and this was attenuated with the expression of unphosphorylatable MLC(20) at the Ser1/Ser2 phosphorylation sites. The present results suggest that the down-regulation of myosin II activity achieved by the phosphorylation at the Ser1/Ser2 sites plays an important role in the normal reorganization of actomyosin filaments triggered by PDGF receptor stimulation.
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Affiliation(s)
- Satoshi Komatsu
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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32
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Ito K, Ikebe M, Kashiyama T, Mogami T, Kon T, Yamamoto K. Kinetic mechanism of the fastest motor protein, Chara myosin. J Biol Chem 2007; 282:19534-45. [PMID: 17488711 DOI: 10.1074/jbc.m611802200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chara corallina class XI myosin is by far the fastest molecular motor. To investigate the molecular mechanism of this fast movement, we performed a kinetic analysis of a recombinant motor domain of Chara myosin. We estimated the time spent in the strongly bound state with actin by measuring rate constants of ADP dissociation from actin.motor domain complex and ATP-induced dissociation of the motor domain from actin. The rate constant of ADP dissociation from acto-motor domain was >2800 s(-1), and the rate constant of ATP-induced dissociation of the motor domain from actin at physiological ATP concentration was 2200 s(-1). From these data, the time spent in the strongly bound state with actin was estimated to be <0.82 ms. This value is the shortest among known values for various myosins and yields the duty ratio of <0.3 with a V(max) value of the actin-activated ATPase activity of 390 s(-1). The addition of the long neck domain of myosin Va to the Chara motor domain largely increased the velocity of the motility without increasing the ATP hydrolysis cycle rate, consistent with the swinging lever model. In addition, this study reveals some striking kinetic features of Chara myosin that are suited for the fast movement: a dramatic acceleration of ADP release by actin (1000-fold) and extremely fast ATP binding rate.
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Affiliation(s)
- Kohji Ito
- Department of Biology, Chiba University, Inage-ku, Chiba 263-8522, Japan.
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33
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Sumiyoshi H, Ooguchi M, Ooi A, Okagaki T, Higashi-Fujime S. Insight into the mechanism of fast movement of myosin from Chara corallina. ACTA ACUST UNITED AC 2007; 64:131-42. [PMID: 17183547 DOI: 10.1002/cm.20171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chara myosin, two-headed plant myosin belonging to class XI, slides F-actin at maximally 60 microm s(-1). To elucidate the mechanism of this fast sliding, we extensively investigated its mechanochemical properties. The maximum actin activated ATPase activity, Vmax, was 21.3 s(-1) head(-1) in a solution, but when myosin was immobilized on the surface, its activity was 57.6 s(-1) head(-1) at 2 mg ml(-1) of F-actin. The sliding velocity and the actin activated ATPase activity were greatly inhibited by ADP, suggesting that ADP dissociation was the rate limiting step. With the extensive assay of motility by varying the surface density, the duty ratio of Chara myosin was found to be 0.49-0.44 from velocity measurements and 0.34 from the landing rate analysis. At the surface density of 10 molecules microm(-2), Chara myosin exhibited pivot movement under physiological conditions. Based on the results obtained, we will discuss the sliding mechanism of Chara myosin according to the working stroke model in terms of its physiological aspects. aspects.
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Affiliation(s)
- Hiroki Sumiyoshi
- Department of Molecular Biology, School of Science, Nagoya University, Chikusaku Nagoya, Japan
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34
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Okada T, Tanaka H, Iwane AH, Kitamura K, Ikebe M, Yanagida T. The diffusive search mechanism of processive myosin class-V motor involves directional steps along actin subunits. Biochem Biophys Res Commun 2007; 354:379-84. [PMID: 17241612 DOI: 10.1016/j.bbrc.2006.12.200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Accepted: 12/25/2006] [Indexed: 11/30/2022]
Abstract
It is widely accepted that the vesicle-transporter myosin-V moves processively along F-actin with large steps of approximately 36 nm using a hand-over-hand mechanism. A key question is how does the rear head of two-headed myosin-V search for the forward actin target in the forward direction. Scanning probe nanometry was used to resolve this underlying search process, which was made possible by attaching the head to a relatively large probe. One-headed myosin-V undergoes directional diffusion with approximately 5.5 nm substeps to develop an average displacement of approximately 20 nm, which was independent of the neck length (2IQ and 6IQ motifs). Two-headed myosin-V showed several approximately 5.5 nm substeps within each processive approximately 36 nm step. These results suggest that the myosin-V head searches in the forward direction for the actin target using directional diffusion on the actin subunits according to a potential slope created along the actin helix.
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Affiliation(s)
- Takuya Okada
- Formation of Soft Nano-Machines, CREST JST, 1-3, Yamadaoka, Suita, Osaka 565-0871, Japan
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35
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Abstract
Recently there has been considerable progress in our understanding of regulation for unconventional myosin-V through elucidation of the structure of its inactive conformation and the factors that affect stability of this conformation. The inactive conformation is a folded compact structure characterized by interactions between the myosin head and the C-terminal cargo binding domain. Concentrations of Ca2+ greater than 10 microM disrupt folding. The 3-D structure determined by cryoelectron tomography of 2-D arrays in one study and electron micrographs of isolated molecules reported in another reveal similar features, but suggest different F-actin affinities for the inactive conformation. This has raised the question of how inactive myosin-V is recycled to other sites for additional rounds of cargo transport.
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Affiliation(s)
- Kenneth A Taylor
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA.
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36
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Geislinger B, Kawai R. Brownian molecular motors driven by rotation-translation coupling. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:011912. [PMID: 16907132 DOI: 10.1103/physreve.74.011912] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2006] [Indexed: 05/11/2023]
Abstract
We investigated three models of Brownian motors which convert rotational diffusion into directed translational motion by switching on and off a potential. In the first model a spatially asymmetric potential generates directed translational motion by rectifying rotational diffusion. It behaves much like a conventional flashing ratchet. The second model utilizes both rotational diffusion and drift to generate translational motion without spatial asymmetry in the potential. This second model can be driven by a combination of a Brownian motor mechanism (diffusion driven) or by powerstroke (drift driven) depending on the chosen parameters. In the third model, elements of both the Brownian motor and powerstroke mechanisms are combined by switching between three distinct states. Relevance of the model to biological motor proteins is discussed.
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Affiliation(s)
- Brian Geislinger
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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37
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Frank DJ, Martin SR, Gruender BNT, Lee YSR, Simonette RA, Bayley PM, Miller KG, Beckingham KM. Androcam is a tissue-specific light chain for myosin VI in the Drosophila testis. J Biol Chem 2006; 281:24728-36. [PMID: 16790438 DOI: 10.1074/jbc.m602094200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin VI, a ubiquitously expressed unconventional myosin, has roles in a broad array of biological processes. Unusual for this motor family, myosin VI moves toward the minus (pointed) end of actin filaments. Myosin VI has two light chain binding sites that can both bind calmodulin (CaM). However unconventional myosins could use tissue-specific light chains to modify their activity. In the Drosophila testis, myosin VI is important for maintenance of moving actin structures, called actin cones, which mediate spermatid individualization. A CaM-related protein, Androcam (Acam), is abundantly expressed in the testis and like myosin VI, accumulates on these cones. We have investigated the possibility that Acam is a testis-specific light chain of Drosophila myosin VI. We find that Acam and myosin VI precisely colocalize at the leading edge of the actin cones and that myosin VI is necessary for this Acam localization. Further, myosin VI and Acam co-immunoprecipitate from the testis and interact in yeast two-hybrid assays. Finally Acam binds with high affinity to peptide versions of both myosin VI light chain binding sites. In contrast, although Drosophila CaM also shows high affinity interactions with these peptides, we cannot detect a CaM/myosin VI interaction in the testis. We conclude that Acam and not CaM acts as a myosin VI light chain in the Drosophila testis and hypothesize that it may alter the regulation of myosin VI in this tissue.
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Affiliation(s)
- Deborah J Frank
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA
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38
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Li XD, Jung HS, Mabuchi K, Craig R, Ikebe M. The globular tail domain of myosin Va functions as an inhibitor of the myosin Va motor. J Biol Chem 2006; 281:21789-21798. [PMID: 16757473 DOI: 10.1074/jbc.m602957200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The actin-activated ATPase activity of full-length mammalian myosin Va is well regulated by Ca2+, whereas that of truncated myosin Va without the C-terminal globular tail domain (GTD) is not. Here, we have found that exogenous GTD is capable of inhibiting the actin-activated ATPase activity of GTD-deleted myosin Va. A series of truncated constructs of myosin Va further showed that the entire length of the first coiled-coil (coil-1) of the tail domain is critical for GTD-dependent regulation of myosin Va and that deletion of 58 residues from the C-terminal end of coil-1 markedly hampered regulation. Negative staining electron microscopy revealed that GTD-deleted myosin Va formed a "Y"-shaped structure, which was converted to a triangular shape, similar to the structure of full-length myosin Va in the inhibited state, by addition of exogenous GTD. In contrast, the triangular shape was not observed when the C-terminal 58 residues of coil-1 were deleted, even in the presence of exogenous GTD. Based on these results, we propose a model for the formation of the inhibited state of myosin Va. GTD binds to the C-terminal end of coil-1. The neck-tail junction of myosin Va is flexible, and the long neck enables the head domain to reach the GTD associated with the end of coil-1. Once the head interacts with the GTD, the triangular inhibited conformation is stabilized. Consistent with this model, we found that shortening of the neck of myosin Va by two IQ motifs abolished the regulation by GTD, whereas regulation was partially restored by shortening of coil-1 by an amount comparable to that of the two IQ motifs.
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Affiliation(s)
- Xiang-Dong Li
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655.
| | - Hyun Suk Jung
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Katsuhide Mabuchi
- Muscle Research Group, Boston Biomedical Research Institute, Watertown, Massachusetts 02472
| | - Roger Craig
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Mitsuo Ikebe
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
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39
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Liu J, Taylor DW, Krementsova EB, Trybus KM, Taylor KA. Three-dimensional structure of the myosin V inhibited state by cryoelectron tomography. Nature 2006; 442:208-11. [PMID: 16625208 DOI: 10.1038/nature04719] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Accepted: 03/15/2006] [Indexed: 11/08/2022]
Abstract
Unconventional myosin V (myoV) is an actin-based molecular motor that has a key function in organelle and mRNA transport, as well as in membrane trafficking. MyoV was the first member of the myosin superfamily shown to be processive, meaning that a single motor protein can 'walk' hand-over-hand along an actin filament for many steps before detaching. Full-length myoV has a low actin-activated MgATPase activity at low [Ca2+], whereas expressed constructs lacking the cargo-binding domain have a high activity regardless of [Ca2+] (refs 5-7). Hydrodynamic data and electron micrographs indicate that the active state is extended, whereas the inactive state is compact. Here we show the first three-dimensional structure of the myoV inactive state. Each myoV molecule consists of two heads that contain an amino-terminal motor domain followed by a lever arm that binds six calmodulins. The heads are followed by a coiled-coil dimerization domain (S2) and a carboxy-terminal globular cargo-binding domain. In the inactive structure, bending of myoV at the head-S2 junction places the cargo-binding domain near the motor domain's ATP-binding pocket, indicating that ATPase inhibition might occur through decreased rates of nucleotide exchange. The actin-binding interfaces are unobstructed, and the lever arm is oriented in a position typical of strong actin-binding states. This structure indicates that motor recycling after cargo delivery might occur through transport on actively treadmilling actin filaments rather than by diffusion.
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Affiliation(s)
- Jun Liu
- The Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306-4380, USA
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40
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Ikebe M, Li XD, Mabuchi K, Ikebe R. Conformational change and regulation of myosin molecules. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 565:61-72; discussion 72, 359-69. [PMID: 16106967 DOI: 10.1007/0-387-24990-7_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- Mitsuo Ikebe
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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41
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Debreczeni JE, Farkas L, Harmat V, Hetényi C, Hajdú I, Závodszky P, Kohama K, Nyitray L. Structural Evidence for Non-canonical Binding of Ca2+ to a Canonical EF-hand of a Conventional Myosin. J Biol Chem 2005; 280:41458-64. [PMID: 16227209 DOI: 10.1074/jbc.m506315200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously identified a single inhibitory Ca2+-binding site in the first EF-hand of the essential light chain of Physarum conventional myosin (Farkas, L., Malnasi-Csizmadia, A., Nakamura, A., Kohama, K., and Nyitray, L. (2003) J. Biol. Chem. 278, 27399-27405). As a general rule, conformation of the EF-hand-containing domains in the calmodulin family is "closed" in the absence and "open" in the presence of bound cations; a notable exception is the unusual Ca2+-bound closed domain in the essential light chain of the Ca2+-activated scallop muscle myosin. Here we have reported the 1.8 A resolution structure of the regulatory domain (RD) of Physarum myosin II in which Ca2+ is bound to a canonical EF-hand that is also in a closed state. The 12th position of the EF-hand loop, which normally provides a bidentate ligand for Ca2+ in the open state, is too far in the structure to participate in coordination of the ion. The structure includes a second Ca2+ that only mediates crystal contacts. To reveal the mechanism behind the regulatory effect of Ca2+, we compared conformational flexibilities of the liganded and unliganded RD. Our working hypothesis, i.e. the modulatory effect of Ca2+ on conformational flexibility of RD, is in line with the observed suppression of hydrogen-deuterium exchange rate in the Ca2+-bound form, as well as with results of molecular dynamics calculations. Based on this evidence, we concluded that Ca2+-induced change in structural dynamics of RD is a major factor in Ca2+-mediated regulation of Physarum myosin II activity.
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Affiliation(s)
- Judit E Debreczeni
- Department of Biochemistry, Eötvös Loránd University, Budapest H-1117, Hungary
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42
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Terrak M, Rebowski G, Lu RC, Grabarek Z, Dominguez R. Structure of the light chain-binding domain of myosin V. Proc Natl Acad Sci U S A 2005; 102:12718-23. [PMID: 16120677 PMCID: PMC1200277 DOI: 10.1073/pnas.0503899102] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosin V is a double-headed molecular motor involved in organelle transport. Two distinctive features of this motor, processivity and the ability to take extended linear steps of approximately 36 nm along the actin helical track, depend on its unusually long light chain-binding domain (LCBD). The LCBD of myosin V consists of six tandem IQ motifs, which constitute the binding sites for calmodulin (CaM) and CaM-like light chains. Here, we report the 2-A resolution crystal structure of myosin light chain 1 (Mlc1p) bound to the IQ2-IQ3 fragment of Myo2p, a myosin V from Saccharomyces cerevisiae. This structure, combined with FRET distance measurements between probes in various CaM-IQ complexes, comparative sequence analysis, and the previously determined structures of Mlc1p-IQ2 and Mlc1p-IQ4, allowed building a model of the LCBD of myosin V. The IQs of myosin V are distributed into three pairs. There appear to be specific cooperative interactions between light chains within each IQ pair, but little or no interaction between pairs, providing flexibility at their junctions. The second and third IQ pairs each present a light chain, whether CaM or a CaM-related molecule, bound in a noncanonical extended conformation in which the N-lobe does not interact with the IQ motif. The resulting free N-lobes may engage in protein-protein interactions. The extended conformation is characteristic of the single IQ of myosin VI and is common throughout the myosin superfamily. The model points to a prominent role of the LCBD in the function, regulation, and molecular interactions of myosin V.
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Affiliation(s)
- Mohammed Terrak
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472, USA
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43
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Watanabe M, Nomura K, Ohyama A, Ishikawa R, Komiya Y, Hosaka K, Yamauchi E, Taniguchi H, Sasakawa N, Kumakura K, Ushiki T, Sato O, Ikebe M, Igarashi M. Myosin-Va regulates exocytosis through the submicromolar Ca2+-dependent binding of syntaxin-1A. Mol Biol Cell 2005; 16:4519-30. [PMID: 16030255 PMCID: PMC1237061 DOI: 10.1091/mbc.e05-03-0252] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Myosin-Va is an actin-based processive motor that conveys intracellular cargoes. Synaptic vesicles are one of the most important cargoes for myosin-Va, but the role of mammalian myosin-Va in secretion is less clear than for its yeast homologue, Myo2p. In the current studies, we show that myosin-Va on synaptic vesicles interacts with syntaxin-1A, a t-SNARE involved in exocytosis, at or above 0.3 microM Ca2+. Interference with formation of the syntaxin-1A-myosin-Va complex reduces the exocytotic frequency in chromaffin cells. Surprisingly, the syntaxin-1A-binding site was not in the tail of myosin-Va but rather in the neck, a region that contains calmodulin-binding IQ-motifs. Furthermore, we found that syntaxin-1A binding by myosin-Va in the presence of Ca2+ depends on the release of calmodulin from the myosin-Va neck, allowing syntaxin-1A to occupy the vacant IQ-motif. Using an anti-myosin-Va neck antibody, which blocks this binding, we demonstrated that the step most important for the antibody's inhibitory activity is the late sustained phase, which is involved in supplying readily releasable vesicles. Our results demonstrate that the interaction between myosin-Va and syntaxin-1A is involved in exocytosis and suggest that the myosin-Va neck contributes not only to the large step size but also to the regulation of exocytosis by Ca2+.
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Affiliation(s)
- Michitoshi Watanabe
- Division of Molecular and Cellular Biology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata 951-8510, Japan
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44
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Li XD, Ikebe R, Ikebe M. Activation of myosin Va function by melanophilin, a specific docking partner of myosin Va. J Biol Chem 2005; 280:17815-22. [PMID: 15760894 DOI: 10.1074/jbc.m413295200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It is known that melanophilin is a myosin Va-targeting molecule that links myosin Va and the cargo vesicles in cells. Here we found that melanophilin directly activates the actin-activated ATPase activity of myosin Va and thus its motor activity. The actin-activated ATPase activity of the melanocyte-type myosin Va having exon-F was significantly activated by melanophilin by 4-fold. Although Rab27a binds to myosin Va/melanophilin complex, it did not affect the melanophilin-induced activation of myosin Va. Deletion of the C-terminal actin binding domain and N-terminal Rab binding domain of melanophilin resulted in no change in the activation of the ATPase by melanophilin, indicating that the myosin Va binding domain (MBD) is sufficient for the activation of myosin Va. Among MBDs, the interaction of MBD-2 with exon-F of myosin Va is critical for the binding of myosin Va and melanophilin, whereas MBD-1 interacting with the globular tail of myosin Va plays a more significant role in the activation of myosin Va ATPase activity. This is the first demonstration that the binding of the cargo molecule directly activates myosin motor activity. The present finding raises the idea that myosin motors are switched upon their binding to the cargo molecules, thus avoiding the waste of ATP consumption.
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Affiliation(s)
- Xiang-Dong Li
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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45
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Nguyen H, Higuchi H. Motility of myosin V regulated by the dissociation of single calmodulin. Nat Struct Mol Biol 2005; 12:127-32. [PMID: 15665867 DOI: 10.1038/nsmb894] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 12/16/2004] [Indexed: 11/09/2022]
Abstract
Myosin V is a calmodulin-binding motor protein. The dissociation of single calmodulin molecules from individual myosin V molecules at 1 microM Ca(2+) correlates with a reduction in sliding velocity in an in vitro motility assay. The dissociation of two calmodulin molecules at 5 microM Ca(2+) correlates with a detachment of actin filaments from myosin V. To mimic the regulation of myosin V motility by Ca(2+) in a cell, caged Ca(2+) coupled with a UV flash system was used to produce Ca(2+) transients. During the Ca(2+) transient, myosin V goes through the functional cycle of reduced sliding velocity, actin detachment and reattachment followed by the recovery of the sliding velocity. These results indicate that myosin V motility is regulated by Ca(2+) through a reduction in actin-binding affinity resulting from the dissociation of single calmodulin molecules.
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Affiliation(s)
- HoaAnh Nguyen
- Center for Interdisciplinary Research, Tohoku University, Sendai 980-8578, Japan
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46
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Abstract
The majority of active transport in the cell is driven by three classes of molecular motors: the kinesin and dynein families that move toward the plus-end and minus-end of microtubules, respectively, and the unconventional myosin motors that move along actin filaments. Each class of motor has different properties, but in the cell they often function together. In this review we summarize what is known about their single-molecule properties and the possibilities for regulation of such properties. In view of new results on cytoplasmic dynein, we attempt to rationalize how these different classes of motors might work together as part of the intracellular transport machinery. We propose that kinesin and myosin are robust and highly efficient transporters, but with somewhat limited room for regulation of function. Because cytoplasmic dynein is less efficient and robust, to achieve function comparable to the other motors it requires a number of accessory proteins as well as multiple dyneins functioning together. This necessity for additional factors, as well as dynein's inherent complexity, in principle allows for greatly increased control of function by taking the factors away either singly or in combination. Thus, dynein's contribution relative to the other motors can be dynamically tuned, allowing the motors to function together differently in a variety of situations.
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Affiliation(s)
- Roop Mallik
- Department of Developmental and Cell Biology, University of California Irvine, California 92697, USA
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47
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Martin SR, Bayley PM. Calmodulin bridging of IQ motifs in myosin-V. FEBS Lett 2004; 567:166-70. [PMID: 15178316 DOI: 10.1016/j.febslet.2004.04.053] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Revised: 04/14/2004] [Accepted: 04/23/2004] [Indexed: 11/18/2022]
Abstract
Ca(2+)-saturated calmodulin binds to double-length IQ lever-arm sequences from murine myosin-V, forming a 1:1 "bridging" complex with very high affinity, (K9d)<10 pM for double motifs, IQ34, IQ45 and IQ56). Such a 1:1 complex involves interaction of one calmodulin (CaM) molecule with two adjacent IQ-motifs, providing a molecular mechanism for the observed Ca(2+)-dependent CaM dissociation from the IQ-region. Structural considerations suggest that formation of the 1:1 complex requires a severe distortion of the lever-arm, potentially regulating functional motility. This would be consistent with a recent report of diverse, irregular shapes of the lever arm of myosin-V induced by the presence of Ca(2+).
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Affiliation(s)
- Stephen R Martin
- Division of Physical Biochemistry, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
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48
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Tokuo H, Ikebe M. Myosin X transports Mena/VASP to the tip of filopodia. Biochem Biophys Res Commun 2004; 319:214-20. [PMID: 15158464 DOI: 10.1016/j.bbrc.2004.04.167] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Indexed: 11/16/2022]
Abstract
Myosin X (M10) is a two-headed actin based motor expressed in a variety of cell types, that is thought to play a role in cargo movement in mammalian cells, but its cellular function is unknown. Here we found that M10 binds to Mena/VASP, which facilitates actin polymerization by competing with actin capping proteins. Immunocytochemistry revealed that endogenous M10 co-localized with Mena/VASP at the tip of filopodia. Consistently, both EGFP-M10 and RFP-VASP were found at the tip of filopodia. The result raises a hypothesis that M10 transports Mena/VASP towards the tip of filopodia. Supporting this idea, the amount of VASP at the tip of filopodia was proportional to that of M10. Furthermore, we directly visualized the movement of M10 and VASP in living HeLa cells under fluorescence microscope. EGFP-M10 and RFP-VASP move together from the root to the tip of the filopodia. Interestingly, the amount of M10 at the tip of filopodia was linearly related to the length of filopodia, consistent with the actin filament extending function of VASP. These results show that M10 is a specific motor carrying Mena/VASP from the root to the tip of the filopodia where extension of actin filament takes place.
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Affiliation(s)
- Hiroshi Tokuo
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
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49
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Lau P, Nixon SJ, Parton RG, Muscat GEO. RORalpha regulates the expression of genes involved in lipid homeostasis in skeletal muscle cells: caveolin-3 and CPT-1 are direct targets of ROR. J Biol Chem 2004; 279:36828-40. [PMID: 15199055 DOI: 10.1074/jbc.m404927200] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The staggerer mice carry a deletion in the RORalpha gene and have a prolonged humoral response, overproduce inflammatory cytokines, and are immunodeficient. Furthermore, the staggerer mice display lowered plasma apoA-I/-II, decreased plasma high density lipoprotein cholesterol and triglycerides, and develop hypo-alpha-lipoproteinemia and atherosclerosis. However, relatively little is known about RORalpha in the context of target tissues, target genes, and lipid homeostasis. For example, RORalpha is abundantly expressed in skeletal muscle, a major mass peripheral tissue that accounts for approximately 40% of total body weight and 50% of energy expenditure. This lean tissue is a primary site of glucose disposal and fatty acid oxidation. Consequently, muscle has a significant role in insulin sensitivity, obesity, and the blood-lipid profile. In particular, the role of RORalpha in skeletal muscle metabolism has not been investigated, and the contribution of skeletal muscle to the ROR-/- phenotype has not been resolved. We utilize ectopic dominant negative RORalpha expression in skeletal muscle cells to understand the regulatory role of RORs in this major mass peripheral tissue. Exogenous dominant negative RORalpha expression in skeletal muscle cells represses the endogenous levels of RORalpha and -gamma mRNAs and ROR-dependent gene expression. Moreover, we observed attenuated expression of many genes involved in lipid homeostasis. Furthermore, we show that the muscle carnitine palmitoyltransferase-1 and caveolin-3 promoters are directly regulated by ROR and coactivated by p300 and PGC-1. This study implicates RORs in the control of lipid homeostasis in skeletal muscle. In conclusion, we speculate that ROR agonists would increase fatty acid catabolism in muscle and suggest selective activators of ROR may have therapeutic utility in the treatment of obesity and atherosclerosis.
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Affiliation(s)
- Patrick Lau
- Institute for Molecular Bioscience, Division of Molecular Genetics and Development, School of Biomedical Sciences, University of Queensland, St. Lucia, Queensland 4072, Australia
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50
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Sato O, White HD, Inoue A, Belknap B, Ikebe R, Ikebe M. Human deafness mutation of myosin VI (C442Y) accelerates the ADP dissociation rate. J Biol Chem 2004; 279:28844-54. [PMID: 15123708 DOI: 10.1074/jbc.m314332200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The missense mutation of Cys(442) to Tyr of myosin VI causes progressive postlingual sensorineural deafness. Here we report the affects of the C442Y mutation on the kinetics of the actomyosin ATP hydrolysis mechanism and motor function of myosin VI. The largest changes in the kinetic mechanism of ATP hydrolysis produced by the C442Y mutation are about 10-fold increases in the rate of ADP dissociation from both myosin VI and actomyosin VI. The rates of ADP dissociation from acto-C442Y myosin VI-ADP and C442Y myosin VI-ADP are 20-40 times more rapid than the steady state rates and cannot be the rate-limiting steps of the hydrolysis mechanism in the presence or absence of actin. The 2-fold increase in the actin gliding velocity of C442Y compared with wild type (WT) may be explained at least in part by the more rapid rate of ADP dissociation. The C442Y myosin VI has a significant increase ( approximately 10-fold) in the steady state ATPase rate in the absence of actin relative to WT myosin VI. The steady state rate of actin-activated ATP hydrolysis is unchanged by the C442Y mutation at low (<10(-7) m) calcium but is calcium-sensitive with a 1.6-fold increase at high ( approximately 10(-4) m) calcium that does not occur with WT. The actin gliding velocity of the C442Y mutant decreases significantly at low surface density of myosin VI, suggesting that the mutation hampers the processive movement of myosin VI.
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Affiliation(s)
- Osamu Sato
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655-0127, USA
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