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Yao LL, Hou WD, Liang Y, Li XD, Ji HH. Spire2 and Rab11a synergistically activate myosin-5b motor function. Biochem Biophys Res Commun 2024; 703:149653. [PMID: 38364682 DOI: 10.1016/j.bbrc.2024.149653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/29/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024]
Abstract
Cellular vesicle long-distance transport along the cytoplasmic actin network has recently been uncovered in several cell systems. In metaphase mouse oocytes, the motor protein myosin-5b (Myo5b) and the actin nucleation factor Spire are recruited to the Rab11a-positive vesicle membrane, forming a ternary complex of Myo5b/Spire/Rab11a that drives the vesicle long-distance transport to the oocyte cortex. However, the mechanism underlying the intermolecular regulation of the Myo5b/Spire/Rab11a complex remains unknown. In this study, we expressed and purified Myo5b, Spire2, and Rab11a proteins, and performed ATPase activity measurements, pulldown and single-molecule motility assays. Our results demonstrate that both Spire2 and Rab11a are required to activate Myo5b motor activity under physiological ionic conditions. The GTBM fragment of Spire2 stimulates the ATPase activity of Myo5b, while Rab11a enhances this activation. This activation occurs by disrupting the head-tail interaction of Myo5b. Furthermore, at the single-molecule level, we observed that the GTBM fragment of Spire2 and Rab11a coordinate to stimulate the Myo5b motility activity. Based on our results, we propose that upon association with the vesicle membrane, Myo5b, Spire2 and Rab11a form a ternary complex, and the inhibited Myo5b is synergistically activated by Spire2 and Rab11a, thereby triggering the long-distance transport of vesicles.
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Affiliation(s)
- Lin-Lin Yao
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China
| | - Wei-Dong Hou
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China
| | - Yi Liang
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China
| | - Xiang-Dong Li
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Huan-Hong Ji
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Jiangxi Medical College, Nanchang University, Nanchang, 330006, PR China.
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2
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Niu F, Liu Y, Sun K, Xu S, Dong J, Yu C, Yan K, Wei Z. Autoinhibition and activation mechanisms revealed by the triangular-shaped structure of myosin Va. SCIENCE ADVANCES 2022; 8:eadd4187. [PMID: 36490350 PMCID: PMC9733927 DOI: 10.1126/sciadv.add4187] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 11/03/2022] [Indexed: 06/17/2023]
Abstract
As the prototype of unconventional myosin motor family, myosin Va (MyoVa) transport cellular cargos along actin filaments in diverse cellular processes. The off-duty MyoVa adopts a closed and autoinhibited state, which can be relieved by cargo binding. The molecular mechanisms governing the autoinhibition and activation of MyoVa remain unclear. Here, we report the cryo-electron microscopy structure of the two full-length, closed MyoVa heavy chains in complex with 12 calmodulin light chains at 4.78-Å resolution. The MyoVa adopts a triangular structure with multiple intra- and interpolypeptide chain interactions in establishing the closed state with cargo binding and adenosine triphosphatase activity inhibited. Structural, biochemical, and cellular analyses uncover an asymmetric autoinhibition mechanism, in which the cargo-binding sites in the two MyoVa heavy chains are differently protected. Thus, specific and efficient MyoVa activation requires coincident binding of multiple cargo adaptors, revealing an intricate and elegant activity regulation of the motor in response to cargos.
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Affiliation(s)
- Fengfeng Niu
- Brain Research Center, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yong Liu
- Brain Research Center, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- SUSTech-HIT Joint PhD Program, Harbin Institute of Technology, Harbin, Heilongjiang, China
| | - Kang Sun
- Brain Research Center, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Shun Xu
- Brain Research Center, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Jiayuan Dong
- Brain Research Center, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Cong Yu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research and Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, Guangdong, China
| | - Kaige Yan
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Zhiyi Wei
- Brain Research Center, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
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3
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Haraguchi T, Ito K, Morikawa T, Yoshimura K, Shoji N, Kimura A, Iwaki M, Tominaga M. Autoregulation and dual stepping mode of MYA2, an Arabidopsis myosin XI responsible for cytoplasmic streaming. Sci Rep 2022; 12:3150. [PMID: 35210477 PMCID: PMC8873201 DOI: 10.1038/s41598-022-07047-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 02/08/2022] [Indexed: 11/09/2022] Open
Abstract
Arabidopsis thaliana has 13 genes belonging to the myosin XI family. Myosin XI-2 (MYA2) plays a major role in the generation of cytoplasmic streaming in Arabidopsis cells. In this study, we investigated the molecular properties of MYA2 expressed by the baculovirus transfer system. Actin-activated ATPase activity and in vitro motility assays revealed that activity of MYA2 was regulated by the globular tail domain (GTD). When the GTD is not bound to the cargo, the GTD inhibits ADP dissociation from the motor domain. Optical nanometry of single MYA2 molecules, combining total internal reflection fluorescence microscopy (TIRFM) and the fluorescence imaging with one-nanometer accuracy (FIONA) method, revealed that the MYA2 processively moved on actin with three different step sizes: − 28 nm, 29 nm, and 60 nm, at low ATP concentrations. This result indicates that MYA2 uses two different stepping modes; hand-over-hand and inchworm-like. Force measurement using optical trapping showed the stall force of MYA2 was 0.85 pN, which was less than half that of myosin V (2–3 pN). These results indicated that MYA2 has different transport properties from that of the myosin V responsible for vesicle transport in animal cells. Such properties may enable multiple myosin XIs to transport organelles quickly and smoothly, for the generation of cytoplasmic streaming in plant cells.
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Affiliation(s)
- Takeshi Haraguchi
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
| | - Kohji Ito
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan.
| | | | - Kohei Yoshimura
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
| | - Nao Shoji
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
| | - Atsushi Kimura
- Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
| | - Mitsuhiro Iwaki
- RIKEN Center for Biosystems Dynamics Research, RIKEN, Osaka, Japan.
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan. .,Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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4
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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: 13] [Impact Index Per Article: 6.5] [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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Frank M, Citarella CG, Quinones GB, Bentley M. A novel labeling strategy reveals that myosin Va and myosin Vb bind the same dendritically polarized vesicle population. Traffic 2020; 21:689-701. [PMID: 32959500 DOI: 10.1111/tra.12764] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/17/2020] [Accepted: 09/17/2020] [Indexed: 12/14/2022]
Abstract
Neurons are specialized cells with a polarized geometry and several distinct subdomains that require specific complements of proteins. Delivery of transmembrane proteins requires vesicle transport, which is mediated by molecular motor proteins. The myosin V family of motor proteins mediates transport to the barbed end of actin filaments, and little is known about the vesicles bound by myosin V in neurons. We developed a novel strategy to visualize myosin V-labeled vesicles in cultured hippocampal neurons and systematically characterized the vesicle populations labeled by myosin Va and Vb. We find that both myosins bind vesicles that are polarized to the somatodendritic domain where they undergo bidirectional long-range transport. A series of two-color imaging experiments showed that myosin V specifically colocalized with two different vesicle populations: vesicles labeled with the transferrin receptor and vesicles labeled by low-density lipoprotein receptor. Finally, coexpression with Kinesin-3 family members found that myosin V binds vesicles concurrently with KIF13A or KIF13B, supporting the hypothesis that coregulation of kinesins and myosin V on vesicles is likely to play an important role in neuronal vesicle transport. We anticipate that this new assay will be applicable in a broad range of cell types to determine the function of myosin V motor proteins.
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Affiliation(s)
- Madeline Frank
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Clara G Citarella
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Geraldine B Quinones
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Marvin Bentley
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
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6
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Roles of Myosin-Mediated Membrane Trafficking in TGF-β Signaling. Int J Mol Sci 2019; 20:ijms20163913. [PMID: 31408934 PMCID: PMC6719161 DOI: 10.3390/ijms20163913] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 12/17/2022] Open
Abstract
Recent findings have revealed the role of membrane traffic in the signaling of transforming growth factor-β (TGF-β). These findings originate from the pivotal function of TGF-β in development, cell proliferation, tumor metastasis, and many other processes essential in malignancy. Actin and unconventional myosin have crucial roles in subcellular trafficking of receptors; research has also revealed a growing number of unconventional myosins that have crucial roles in TGF-β signaling. Unconventional myosins modulate the spatial organization of endocytic trafficking and tether membranes or transport them along the actin cytoskeletons. Current models do not fully explain how membrane traffic forms a bridge between TGF-β and the downstream effectors that produce its functional responsiveness, such as cell migration. In this review, we present a brief overview of the current knowledge of the TGF-β signaling pathway and the molecular components that comprise the core pathway as follows: ligands, receptors, and Smad mediators. Second, we highlight key role(s) of myosin motor-mediated protein trafficking and membrane domain segregation in the modulation of the TGF-β signaling pathway. Finally, we review future challenges and provide future prospects in this field.
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7
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Cao QJ, Zhang N, Zhou R, Yao LL, Li XD. The cargo adaptor proteins RILPL2 and melanophilin co-regulate myosin-5a motor activity. J Biol Chem 2019; 294:11333-11341. [PMID: 31175157 DOI: 10.1074/jbc.ra119.007384] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 06/03/2019] [Indexed: 11/06/2022] Open
Abstract
Vertebrate myosin-5a is an ATP-utilizing processive motor associated with the actin network and responsible for the transport and localization of several vesicle cargoes. To transport cargo efficiently and prevent futile ATP hydrolysis, myosin-5a motor function must be tightly regulated. The globular tail domain (GTD) of myosin-5a not only functions as the inhibitory domain but also serves as the binding site for a number of cargo adaptor proteins, including melanophilin (Mlph) and Rab-interacting lysosomal protein-like 2 (RILPL2). In this study, using various biochemical approaches, including ATPase, single-molecule motility, GST pulldown assays, and analytical ultracentrifugation, we demonstrate that the binding of both Mlph and RILPL2 to the GTD of myosin-5a is required for the activation of myosin-5a motor function under physiological ionic conditions. We also found that this activation is regulated by the small GTPase Rab36, a binding partner of RILPL2. In summary, our results indicate that RILPL2 is required for Mlph-mediated activation of Myo5a motor activity under physiological conditions and that Rab36 promotes this activation. We propose that Rab36 stimulates RILPL2 to interact with the myosin-5a GTD; this interaction then induces exposure of the Mlph-binding site in the GTD, enabling Mlph to interact with the GTD and activate myosin-5a motor activity.
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Affiliation(s)
- Qing-Juan Cao
- 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
| | - 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
| | - Rui Zhou
- 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
| | - 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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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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9
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Barlan K, Gelfand VI. Microtubule-Based Transport and the Distribution, Tethering, and Organization of Organelles. Cold Spring Harb Perspect Biol 2017; 9:9/5/a025817. [PMID: 28461574 DOI: 10.1101/cshperspect.a025817] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
SUMMARYMicrotubules provide long tracks along which a broad range of organelles and vesicles are transported by kinesin and dynein motors. Motor protein complexes also tether cargoes to cytoskeletal filaments, helping facilitate their interaction and communication. The generation of biochemically distinct microtubule subpopulations allows subsets of motors to recognize a given microtubule identity, allowing further organization within the cytoplasm. Both transport and tethering are spatiotemporally regulated through multiple modes, including acute modification of both motor-cargo and motor-track associations by various physiological signals. Strict regulation of intracellular transport is particularly important in specialized cell types such as neurons. Here, we review general mechanisms by which cargo transport is controlled and also highlight examples of transport regulated by multiple mechanisms.
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Affiliation(s)
- Kari Barlan
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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10
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Yao LL, Shen M, Lu Z, Ikebe M, Li XD. Identification of the Isoform-specific Interactions between the Tail and the Head of Class V Myosin. J Biol Chem 2016; 291:8241-50. [PMID: 26912658 DOI: 10.1074/jbc.m115.693762] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Indexed: 12/23/2022] Open
Abstract
Vertebrates have three isoforms of class V myosin (Myo5), Myo5a, Myo5b, and Myo5c, which are involved in transport of multiple cargoes. It is well established that the motor functions of Myo5a and Myo5b are regulated by a tail inhibition mechanism. Here we found that the motor function of Myo5c was also inhibited by its globular tail domain (GTD), and this inhibition was abolished by high Ca(2+), indicating that the tail inhibition mechanism is conserved in vertebrate Myo5. Interestingly, we found that Myo5a-GTD and Myo5c-GTD were not interchangeable in terms of inhibition of motor function, indicating isoform-specific interactions between the GTD and the head of Myo5. To identify the isoform-specific interactions, we produced a number of Myo5 chimeras by swapping the corresponding regions of Myo5a and Myo5c. We found that Myo5a-GTD, with its H11-H12 loop being substituted with that of Myo5c, was able to inhibit the ATPase activity of Myo5c and that Myo5a-GTD was able to inhibit the ATPase activity of Myo5c-S1 and Myo5c-HMM only when their IQ1 motif was substituted with that of Myo5a. Those results indicate that the H11-H12 loop in the GTD and the IQ1 motif in the head dictate the isoform-specific interactions between the GTD and head of Myo5. Because the IQ1 motif is wrapped by calmodulin, whose conformation is influenced by the sequence of the IQ1 motif, we proposed that the calmodulin bound to the IQ1 motif interacts with the H11-H12 loop of the GTD in the inhibited state of Myo5.
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Affiliation(s)
- Lin-Lin Yao
- From the 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 and
| | - Mei Shen
- From the 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 and
| | - Zekuan Lu
- From the 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 and
| | - Mitsuo Ikebe
- the Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708
| | - Xiang-dong Li
- From the 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 and
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11
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Conte IL, Hellen N, Bierings R, Mashanov GI, Manneville JB, Kiskin NI, Hannah MJ, Molloy JE, Carter T. Interaction between MyRIP and the actin cytoskeleton regulates Weibel-Palade body trafficking and exocytosis. J Cell Sci 2016; 129:592-603. [PMID: 26675235 PMCID: PMC4760305 DOI: 10.1242/jcs.178285] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 12/03/2015] [Indexed: 12/11/2022] Open
Abstract
Weibel-Palade body (WPB)-actin interactions are essential for the trafficking and secretion of von Willebrand factor; however, the molecular basis for this interaction remains poorly defined. Myosin Va (MyoVa or MYO5A) is recruited to WPBs by a Rab27A-MyRIP complex and is thought to be the prime mediator of actin binding, but direct MyRIP-actin interactions can also occur. To evaluate the specific contribution of MyRIP-actin and MyRIP-MyoVa binding in WPB trafficking and Ca(2+)-driven exocytosis, we used EGFP-MyRIP point mutants with disrupted MyoVa and/or actin binding and high-speed live-cell fluorescence microscopy. We now show that the ability of MyRIP to restrict WPB movement depends upon its actin-binding rather than its MyoVa-binding properties. We also show that, although the role of MyRIP in Ca(2+)-driven exocytosis requires both MyoVa- and actin-binding potential, it is the latter that plays a dominant role. In view of these results and together with the analysis of actin disruption or stabilisation experiments, we propose that the role of MyRIP in regulating WPB trafficking and exocytosis is mediated largely through its interaction with actin rather than with MyoVa.
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Affiliation(s)
- Ianina L Conte
- Cardiovascular and Cell Science Research Institute, St George's University, London SW17 0RE, UK
| | - Nicola Hellen
- The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK
| | - Ruben Bierings
- The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK
| | | | | | - Nikolai I Kiskin
- The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK
| | - Matthew J Hannah
- The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK
| | - Justin E Molloy
- The Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, UK
| | - Tom Carter
- Cardiovascular and Cell Science Research Institute, St George's University, London SW17 0RE, UK
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Sköld HN, Aspengren S, Cheney KL, Wallin M. Fish Chromatophores—From Molecular Motors to Animal Behavior. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 321:171-219. [DOI: 10.1016/bs.ircmb.2015.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Bodor A, Radnai L, Hetényi C, Rapali P, Láng A, Kövér KE, Perczel A, Wahlgren WY, Katona G, Nyitray L. DYNLL2 dynein light chain binds to an extended linear motif of myosin 5a tail that has structural plasticity. Biochemistry 2014; 53:7107-22. [PMID: 25312846 DOI: 10.1021/bi500574z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
LC8 dynein light chains (DYNLL) are conserved homodimeric eukaryotic hub proteins that participate in diverse cellular processes. Among the binding partners of DYNLL2, myosin 5a (myo5a) is a motor protein involved in cargo transport. Here we provide a profound characterization of the DYNLL2 binding motif of myo5a in free and DYNLL2-bound form by using nuclear magnetic resonance spectroscopy, X-ray crystallography, and molecular dynamics simulations. In the free form, the DYNLL2 binding region, located in an intrinsically disordered domain of the myo5a tail, has a nascent helical character. The motif becomes structured and folds into a β-strand upon binding to DYNLL2. Despite differences of the myo5a sequence from the consensus binding motif, one peptide is accommodated in each of the parallel DYNLL2 binding grooves, as for all other known partners. Interestingly, while the core motif shows a similar interaction pattern in the binding groove as seen in other complexes, the flanking residues make several additional contacts, thereby lengthening the binding motif. The N-terminal extension folds back and partially blocks the free edge of the β-sheet formed by the binding motif itself. The C-terminal extension contacts the dimer interface and interacts with symmetry-related residues of the second myo5a peptide. The involvement of flanking residues of the core binding site of myo5a could modify the quaternary structure of the full-length myo5a and affect its biological functions. Our results deepen the knowledge of the diverse partner recognition of DYNLL proteins and provide an example of a Janus-faced linear motif.
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Affiliation(s)
- Andrea Bodor
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, and ‡Department of Biochemistry, Eötvös Loránd University , Budapest, 1117 Hungary
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BMP-2 overexpression augments vascular smooth muscle cell motility by upregulating myosin Va via Erk signaling. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:294150. [PMID: 24790701 PMCID: PMC3980867 DOI: 10.1155/2014/294150] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/11/2013] [Accepted: 12/05/2013] [Indexed: 11/17/2022]
Abstract
Background. The disruption of physiologic vascular smooth muscle cell (VSMC) migration initiates atherosclerosis development. The biochemical mechanisms leading to dysfunctional VSMC motility remain unknown. Recently, cytokine BMP-2 has been implicated in various vascular physiologic and pathologic processes. However, whether BMP-2 has any effect upon VSMC motility, or by what manner, has never been investigated. Methods. VSMCs were adenovirally transfected to genetically overexpress BMP-2. VSMC motility was detected by modified Boyden chamber assay, confocal time-lapse video assay, and a colony wounding assay. Gene chip array and RT-PCR were employed to identify genes potentially regulated by BMP-2. Western blot and real-time PCR detected the expression of myosin Va and the phosphorylation of extracellular signal-regulated kinases 1/2 (Erk1/2). Immunofluorescence analysis revealed myosin Va expression locale. Intracellular Ca2+ oscillations were recorded. Results. VSMC migration was augmented in VSMCs overexpressing BMP-2 in a dose-dependent manner. siRNA-mediated knockdown of myosin Va inhibited VSMC motility. Both myosin Va mRNA and protein expression significantly increased after BMP-2 administration and were inhibited by Erk1/2 inhibitor U0126. BMP-2 induced Ca2+ oscillations, generated largely by a “cytosolic oscillator”. Conclusion. BMP-2 significantly increased VSMCs migration and myosin Va expression, via the Erk signaling pathway and intracellular Ca2+ oscillations. We provide additional insight into the pathophysiology of atherosclerosis, and inhibition of BMP-2-induced myosin Va expression may represent a potential therapeutic strategy.
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Velvarska H, Niessing D. Structural insights into the globular tails of the human type v myosins Myo5a, Myo5b, And Myo5c. PLoS One 2013; 8:e82065. [PMID: 24339992 PMCID: PMC3858360 DOI: 10.1371/journal.pone.0082065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 10/21/2013] [Indexed: 01/11/2023] Open
Abstract
Vertebrate type V myosins (MyoV) Myo5a, Myo5b, and Myo5c mediate transport of several different cargoes. All MyoV paralogs bind to cargo complexes mainly by their C-terminal globular domains. In absence of cargo, the globular domain of Myo5a inhibits its motor domain. Here, we report low-resolution SAXS models for the globular domains from human Myo5a, Myo5b, and Myo5c, which suggest very similar overall shapes of all three paralogs. We determined the crystal structures of globular domains from Myo5a and Myo5b, and provide a homology model for human Myo5c. When we docked the Myo5a crystal structure into a previously published electron microscopy density of the autoinhibited full-length Myo5a, only one domain orientation resulted in a good fit. This structural arrangement suggests the participation of additional region of the globular domain in autoinhibition. Quantification of the interaction of the Myo5a globular domain with its motor complex revealed a tight binding with dissociation half-life in the order of minutes, suggesting a rather slow transition between the active and inactive states.
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Affiliation(s)
- Hana Velvarska
- Institute of Structural Biology; Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-University, München, Germany
| | - Dierk Niessing
- Institute of Structural Biology; Helmholtz Zentrum München – German Research Center for Environmental Health, Neuherberg, Germany
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-University, München, Germany
- * E-mail:
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Nascimento AFZ, Trindade DM, Tonoli CCC, de Giuseppe PO, Assis LHP, Honorato RV, de Oliveira PSL, Mahajan P, Burgess-Brown NA, von Delft F, Larson RE, Murakami MT. Structural insights into functional overlapping and differentiation among myosin V motors. J Biol Chem 2013; 288:34131-34145. [PMID: 24097982 PMCID: PMC3837155 DOI: 10.1074/jbc.m113.507202] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/27/2013] [Indexed: 11/06/2022] Open
Abstract
Myosin V (MyoV) motors have been implicated in the intracellular transport of diverse cargoes including vesicles, organelles, RNA-protein complexes, and regulatory proteins. Here, we have solved the cargo-binding domain (CBD) structures of the three human MyoV paralogs (Va, Vb, and Vc), revealing subtle structural changes that drive functional differentiation and a novel redox mechanism controlling the CBD dimerization process, which is unique for the MyoVc subclass. Moreover, the cargo- and motor-binding sites were structurally assigned, indicating the conservation of residues involved in the recognition of adaptors for peroxisome transport and providing high resolution insights into motor domain inhibition by CBD. These results contribute to understanding the structural requirements for cargo transport, autoinhibition, and regulatory mechanisms in myosin V motors.
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Affiliation(s)
- Andrey F Z Nascimento
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Daniel M Trindade
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Celisa C C Tonoli
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Priscila O de Giuseppe
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Leandro H P Assis
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Rodrigo V Honorato
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Paulo S L de Oliveira
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil
| | - Pravin Mahajan
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | | | - Frank von Delft
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Roy E Larson
- Department of Cellular & Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, São Paulo 14049-900, Brazil
| | - Mario T Murakami
- Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas, São Paulo 13083-100, Brazil.
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Abstract
Specific recognition of the cargo that molecular motors transport or tether to cytoskeleton tracks allows them to perform precise cellular functions at particular times and positions in cells. However, very little is known about how evolution has favored conservation of functions for some isoforms, while also allowing for the generation of new recognition sites and specialized cellular functions. Here we present several crystal structures of the myosin Va or the myosin Vb globular tail domain (GTD) that gives insights into how the motor is linked to the recycling membrane compartments via Rab11 or to the melanosome membrane via recognition of the melanophilin adaptor that binds to Rab27a. The structures illustrate how the Rab11-binding site has been conserved during evolution and how divergence at another site of the GTD allows more specific interactions such as the specific recognition of melanophilin by the myosin Va isoform. With atomic structural insights, these structures also show how either the partner or the GTD structural plasticity upon association is critical for selective recruitment of the motor.
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Abstract
This minireview focuses on recent studies implicating class V myosins in organelle and macromolecule transport within neurons. These studies reveal that class V myosins play important roles in a wide range of fundamental processes occurring within neurons, including the transport into dendritic spines of organelles that support synaptic plasticity, the establishment of neuronal shape, the specification of polarized cargo transport, and the subcellular localization of mRNA.
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Affiliation(s)
- John A Hammer
- From the Cell Biology and Physiology Center, NHLBI, National Institutes of Health, Bethesda, Maryland 20892 and
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Myosin motors at neuronal synapses: drivers of membrane transport and actin dynamics. Nat Rev Neurosci 2013; 14:233-47. [DOI: 10.1038/nrn3445] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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20
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Abstract
Cells use molecular motors, such as myosins, to move, position and segregate their organelles. Class V myosins possess biochemical and structural properties that should make them ideal actin-based cargo transporters. Indeed, studies show that class V myosins function as cargo transporters in yeast, moving a range of organelles, such as the vacuole, peroxisomes and secretory vesicles. There is also increasing evidence in vertebrate cells that class V myosins not only tether organelles to actin but also can serve as short-range, point-to-point organelle transporters, usually following long-range, microtubule-dependent organelle transport.
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Abstract
Advances in live-cell microscopy have revealed the extraordinarily dynamic nature of intracellular organelles. Moreover, movement appears to be critical in establishing and maintaining intracellular organization and organellar and cellular function. Motility is regulated by the activity of organelle-associated motor proteins, kinesins, dyneins and myosins, which move cargo along polar MT (microtubule) and actin tracks. However, in most instances, the motors that move specific organelles remain mysterious. Over recent years, pigment granules, or melanosomes, within pigment cells have provided an excellent model for understanding the molecular mechanisms by which motor proteins associate with and move intracellular organelles. In the present paper, we discuss recent discoveries that shed light on the mechanisms of melanosome transport and highlight future prospects for the use of pigment cells in unravelling general molecular mechanisms of intracellular transport.
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Abstract
In neuroscience, myosin V motor proteins have attracted attention since they are highly expressed in brain, and absence of myosin Va in man leads to a severe neurological disease called Griscelli syndrome. While in some cells myosin V is described to act as a vesicle transport motor, an additional role in exocytosis has emerged recently. In neurons, myosin V has been linked to exocytosis of secretory vesicles and recycling endosomes. Through these functions, it is implied in regulating important brain functions including the release of neuropeptides by exocytosis of large dense-core vesicles and the insertion of neurotransmitter receptors into post-synaptic membranes. This review focuses on the role of myosin V in (i) axonal transport and stimulated exocytosis of large dense-core vesicles to regulate the secretion of neuroactive substances, (ii) tethering of the endoplasmic reticulum at cerebellar synapses to permit long-term depression, (iii) recycling of α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors at hippocampal synapses during long-term potentiation, and (iv) recycling of nicotinic acetylcholine receptors at the neuromuscular junction. Myosin V is thus discussed as an important modulator of synaptic plasticity.
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Affiliation(s)
- Rüdiger Rudolf
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
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Kapitein LC, Hoogenraad CC. Which way to go? Cytoskeletal organization and polarized transport in neurons. Mol Cell Neurosci 2010; 46:9-20. [PMID: 20817096 DOI: 10.1016/j.mcn.2010.08.015] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 08/25/2010] [Indexed: 01/01/2023] Open
Abstract
To establish and maintain their polarized morphology, neurons employ active transport driven by cytoskeletal motor proteins to sort cargo between axons and dendrites. These motors can move in a specific direction over either microtubules (kinesins, dynein) or actin filaments (myosins). The basic traffic rules governing polarized transport on the neuronal cytoskeleton have long remained unclear, but recent work has revealed several fundamental sorting principles based on differences in the cytoskeletal organization in axons versus dendrites. We will highlight the basic characteristics of the neuronal cytoskeleton and review existing evidence for microtubule and actin based traffic rules in polarized neuronal transport. We will propose a model in which polarized sorting of cargo is established by recruiting or activating the proper subset of motor proteins, which are subsequently guided to specific directions by the polarized organization of the neuronal cytoskeleton.
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Affiliation(s)
- Lukas C Kapitein
- Department of Neuroscience, Erasmus Medical Center, Dr. Molewaterplein 50, 3015 GE, Rotterdam, The Netherlands
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Akhmanova A, Hammer JA. Linking molecular motors to membrane cargo. Curr Opin Cell Biol 2010; 22:479-87. [PMID: 20466533 DOI: 10.1016/j.ceb.2010.04.008] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 04/02/2010] [Accepted: 04/16/2010] [Indexed: 12/30/2022]
Abstract
Three types of motors, myosins, kinesins, and cytoplasmic dynein, cooperate to transport intracellular membrane organelles. Transport of each cargo is determined by recruitment of specific sets of motors and their regulation. Targeting of motors to membranes often depends on the formation of large multiprotein assemblies and can be influenced by membrane lipid composition. Motor activity can be regulated by cargo-induced conformational changes such as unfolding or dimerization. The architecture and function of motor: cargo complexes can also be controlled by phosphorylation, calcium signaling, and proteolysis. The complexity of transport systems is further increased by mechanical and functional cross-talk between different types of motors on the same cargo and by participation of the same motor in the movement of different organelles.
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Affiliation(s)
- Anna Akhmanova
- Department of Cell Biology, Erasmus Medical Center, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
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Saneyoshi T, Fortin DA, Soderling TR. Regulation of spine and synapse formation by activity-dependent intracellular signaling pathways. Curr Opin Neurobiol 2009; 20:108-15. [PMID: 19896363 DOI: 10.1016/j.conb.2009.09.013] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2009] [Revised: 09/28/2009] [Accepted: 09/30/2009] [Indexed: 12/26/2022]
Abstract
Formation of the human brain during embryonic and postnatal development is an extraordinarily complex process resulting at maturity in billions of neurons with trillions of specialized connections called synapses. These synapses, composed of a varicosity or bouton from a presynaptic neuron that communicates with a dendritic spine of the postsynaptic neuron, comprise the neural network that is essential for complex behavioral phenomena and cognition. Inappropriate synapse formation or structure is thought to underlie several developmental neuropathologies. Even in the mature CNS, alterations in synapse structure and function continues to be a very dynamic process that is foundational to learning and memory as well as other adaptive abilities of the brain. This synaptic plasticity in mature neurons, which is often triggered by certain patterns of neural activity, is again multifaceted and involves post-translational modifications (e.g. phosphorylation) and subcellular relocalization or trafficking (endocytosis/exocytosis) of existing synaptic proteins, initiation of protein synthesis from existing mRNAs localized in dendrites or spines, and triggering of new gene transcription in the nucleus. These various cellular processes support varying temporal components of synaptic plasticity that begin within 1-2 min but can persist for hours to days. This review will give a critical assessment of activity-dependent molecular modulations of synapses reported over the past couple years. Owing to space limitations, it will focus on mammalian excitatory (i.e. glutamatergic) synapses and will not consider several activity-independent signaling pathways (e.g. ephrinB receptor) that also modulate spine and synapse formation.
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Affiliation(s)
- Takeo Saneyoshi
- Brain Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
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Ramalho JS, Lopes VS, Tarafder AK, Seabra MC, Hume AN. Myrip uses distinct domains in the cellular activation of myosin VA and myosin VIIA in melanosome transport. Pigment Cell Melanoma Res 2009; 22:461-73. [PMID: 19317802 DOI: 10.1111/j.1755-148x.2009.00567.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Myrip is a Rab27a and MyosinVIIa (MyoVIIa) linking protein that may regulate melanosome transport in the retinal pigment epithelium (RPE). Myrip also binds MyosinVa (MyoVa) in vitro however it is unclear whether this interaction is of sufficient affinity to be physiologically relevant. Here, we addressed the questions of whether Myrip interacts with MyoVa in cells and the molecular basis of cellular activation of MyoVa and MyoVIIa by Myrip. To answer these questions we used melanosome transport in skin melanocytes and RPE cells as read-outs of MyoVa and MyoVIIa activity. We found that Myrip recruits and activates MyoVa on skin melanosomes with similar efficiency to the established MyoVa activator Melanophilin (Mlph). Mutagenesis showed that a Myrip-Mlph conserved amphipathic helix (MMAH) is essential for MyoVa interaction while other Myrip regions, including the MyoVa exon F binding domain equivalent, play non-essential roles in this interaction. This suggests that, in contrast to Mlph, Myrip interacts with MyoVa lacking melanocyte-specific exon F. Parallel studies of RPE melanosome transport reveal that Myrip-specific inserts, but not the MMAH, are essential for MyoVIIa activation. We conclude that Myrip is a versatile Rab27a-associated myosin-activating protein that mediates cellular activation of MyoVa and MyoVIIa via non-overlapping domains.
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Affiliation(s)
- José S Ramalho
- Centre of Ophthalmology, Biomedical Institute for Research in Light and Image, University of Coimbra, Coimbra, Portugal
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Chapter 6 New Insights into Melanosome Transport in Vertebrate Pigment Cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 272:245-302. [DOI: 10.1016/s1937-6448(08)01606-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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