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Pan J, Zhou R, Yao LL, Zhang J, Zhang N, Cao QJ, Sun S, Li XD. Identification of a third myosin-5a-melanophilin interaction that mediates the association of myosin-5a with melanosomes. eLife 2024; 13:RP93662. [PMID: 38900147 PMCID: PMC11189624 DOI: 10.7554/elife.93662] [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] [Indexed: 06/21/2024] Open
Abstract
Transport and localization of melanosome at the periphery region of melanocyte are depended on myosin-5a (Myo5a), which associates with melanosome by interacting with its adaptor protein melanophilin (Mlph). Mlph contains four functional regions, including Rab27a-binding domain, Myo5a GTD-binding motif (GTBM), Myo5a exon F-binding domain (EFBD), and actin-binding domain (ABD). The association of Myo5a with Mlph is known to be mediated by two specific interactions: the interaction between the exon-F-encoded region of Myo5a and Mlph-EFBD and that between Myo5a-GTD and Mlph-GTBM. Here, we identify a third interaction between Myo5a and Mlph, that is, the interaction between the exon-G-encoded region of Myo5a and Mlph-ABD. The exon-G/ABD interaction is independent from the exon-F/EFBD interaction and is required for the association of Myo5a with melanosome. Moreover, we demonstrate that Mlph-ABD interacts with either the exon-G or actin filament, but cannot interact with both of them simultaneously. Based on above findings, we propose a new model for the Mlph-mediated Myo5a transportation of melanosomes.
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Affiliation(s)
- Jiabin Pan
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - 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 SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - 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 SciencesBeijingChina
| | - Jie 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 SciencesBeijingChina
| | - 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 SciencesBeijingChina
| | - 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 SciencesBeijingChina
| | - Shaopeng Sun
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - 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 SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
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Kaushik H, Kumar V, Parsad D. Mitochondria-Melanocyte cellular interactions: An emerging mechanism of vitiligo pathogenesis. J Eur Acad Dermatol Venereol 2023; 37:2196-2207. [PMID: 36897230 DOI: 10.1111/jdv.19019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 02/07/2023] [Indexed: 03/11/2023]
Abstract
Mitochondria has emerged as a potential modulator of melanocyte function other than just meeting its cellular ATP demands. Mitochondrial DNA defects are now an established cause of maternal inheritance diseases. Recent cellular studies have highlighted the mitochondrial interaction with other cellular organelles that lead to disease conditions such as in Duchenne muscular dystrophy, where defective mitochondria was found in melanocytes of these patients. Vitiligo, a depigmentory ailment of the skin, is another such disorder whose pathogenesis is now found to be associated with mitochondria. The complete absence of melanocytes at the lesioned site in vitiligo is a fact; however, the precise mechanism of this destruction is still undefined. In this review we have tried to discuss and link the emerging facts of mitochondrial function or its inter- and intra-organellar communications in vitiligo pathogenesis. Mitochondrial close association with melanosomes, molecular involvement in melanocyte-keratinocyte communication and melanocyte survival are new paradigm of melanogenesis that could ultimately account for vitiligo. This definitely adds the new dimensions to our understanding of vitiligo, its management and designing of future mitochondrial targeted therapy for vitiligo.
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Affiliation(s)
- Hitaishi Kaushik
- Department of Dermatology, Venereology & Leprology, PGIMER, Chandigarh, 160012, India
| | - Vinod Kumar
- Department of Dermatology, Venereology & Leprology, PGIMER, Chandigarh, 160012, India
| | - Davinder Parsad
- Department of Dermatology, Venereology & Leprology, PGIMER, Chandigarh, 160012, India
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3
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Gauthier Y, Lepreux S, Cario‐Andre M, Rambert J, Dakdaki A, Lafon M, Abouqal R, Benzekri L. Varicella-zoster virus in actively spreading segmental vitiligo skin: Pathological, immunochemical, and ultrastructural findings (a first and preliminary study). Pigment Cell Melanoma Res 2023; 36:78-85. [PMID: 36112095 PMCID: PMC10092484 DOI: 10.1111/pcmr.13064] [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: 12/04/2021] [Revised: 07/07/2022] [Accepted: 08/15/2022] [Indexed: 12/31/2022]
Abstract
Segmental vitiligo (SV) is a unilateral subtype of vitiligo which is clinically characterized by a cutaneous depigmentation and histologically by a melanocyte loss from the epidermis and hair follicle reservoirs. To date, its pathogenesis remains a mystery. In many cases, this skin depigmentation shares several clinical features and dysfunctions with herpes zoster (HZ). So, for the first time, we examined whether any nucleus and cell fusion associated with a positive immunolabelling of varicella-zoster virus (VZV) and VZV mature virions could be found in SV skin samples as in herpes zoster (HZ). A total of 40 SV samples were used for histological and immunochemical studies. Control samples were obtained from three HZ, and 10 generalized vitiligo lesions. For ultrastructural study, three recent SV and one HZ as controls were recruited. Here, we report that nuclear fusion in epidermal cells were statistically associated with recent SV (p < .001), whereas syncytia formation was associated with long-lasting SV (p = .001). A positive detection of VZV antigen was statistically associated in the epidermis with recent SV and in the dermis with long-lasting SV (p = .001). Finally, the discovery of mature virions in 3/3 recent SV samples provides additional arguments for our viral hypothesis.
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Affiliation(s)
- Yvon Gauthier
- Vitiligo and Melasma Research Association (V.M.R.A.)BordeauxFrance
| | | | - Muriel Cario‐Andre
- Bordeaux University, INSERM, BRIC, U1312BordeauxFrance
- National Reference Center for Rare skin DiseasesBordeaux University HospitalBordeauxFrance
- AquidermBordeauxFrance
| | - Jérome Rambert
- National Reference Center for Rare skin DiseasesBordeaux University HospitalBordeauxFrance
| | - Adrien Dakdaki
- Tumor Bank and Tumor Biology LaboratoryCHU BordeauxPessacFrance
| | - Marie‐Edith Lafon
- Department of Virology Bordeaux University HospitalBordeaux University, CNRS, UMR5234BordeauxFrance
| | - Redouane Abouqal
- Laboratory of Biostatistics, Clinical Research and EpidemiologyMohammed V University in Rabat, Acute Medical Unit, Ibn Sina Teaching HospitalRabatMorocco
| | - Laila Benzekri
- Dermatology Department, Ibn Sina Teaching HospitalMohammed V University in Rabat, Pigmentary Disorders Outpatient ClinicRabatMorocco
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4
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Walcott S, Warshaw DM. Modeling myosin Va liposome transport through actin filament networks reveals a percolation threshold that modulates transport properties. Mol Biol Cell 2021; 33:ar18. [PMID: 34935414 PMCID: PMC9236151 DOI: 10.1091/mbc.e21-08-0389] [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] [Indexed: 11/17/2022] Open
Abstract
Myosin Va (myoVa) motors transport membrane-bound cargo through three-dimensional, intracellular actin filament networks. We developed a coarse-grained, in silico model to predict how actin filament density (3-800 filaments) within a randomly oriented actin network affects fluid-like liposome (350 nm vs. 1750 nm) transport by myoVa motors. Five thousand simulated liposomes transported within each network adopted one of three states: transport, tug-of-war, or diffusion. Diffusion due to liposome detachment from actin rarely occurred given at least 10 motors on the liposome surface. However, with increased actin density, liposomes transitioned from primarily directed transport on single actin filaments to an apparent random walk, resulting from a mixture of transport and tug-of-wars as the probability of encountering additional actin filaments increased. This phase transition arises from a percolation phase transition at a critical number of accessible actin filaments, Nc. Nc is a geometric property of the actin network that depends only on the position and polarity of the actin filaments, transport distance, and the liposome diameter, as evidenced by a fivefold increase in liposome diameter resulting in a fivefold decrease in Nc. Thus in cells, actin network density and cargo size may be regulated to match cargo delivery to the cell’s physiological demands.
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Affiliation(s)
- S Walcott
- Department of Mathematical Sciences, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609
| | - D M Warshaw
- Molecular Physiology and Biophysics, University of Vermont, Health Science Research Facility, 149 Beaumont Avenue, Burlington, VT 05405
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Tian X, Cui Z, Liu S, Zhou J, Cui R. Melanosome transport and regulation in development and disease. Pharmacol Ther 2020; 219:107707. [PMID: 33075361 DOI: 10.1016/j.pharmthera.2020.107707] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 02/06/2023]
Abstract
Melanosomes are specialized membrane-bound organelles that synthesize and organize melanin, ultimately providing color to the skin, hair, and eyes. Disorders in melanogenesis and melanosome transport are linked to pigmentary diseases, such as Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, and Griscelli syndrome. Clinical cases of these pigmentary diseases shed light on the molecular mechanisms that control melanosome-related pathways. However, only an improved understanding of melanogenesis and melanosome transport will further the development of diagnostic and therapeutic approaches. Herein, we review the current literature surrounding melanosomes with particular emphasis on melanosome membrane transport and cytoskeleton-mediated melanosome transport. We also provide perspectives on melanosome regulatory mechanisms which include hormonal action, inflammation, autophagy, and organelle interactions.
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Affiliation(s)
- Xiaoyu Tian
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Ziyong Cui
- Harvard College, Cambridge, MA 02138, United States of America
| | - Song Liu
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Jun Zhou
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan 250014, China; State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Rutao Cui
- Skin Disease Research Institute, The 2nd Hospital, Zhejiang University, Hangzhou 310058, China.
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CMT-308, a Nonantimicrobial Chemically-Modified Tetracycline, Exhibits Anti-Melanogenic Activity by Suppression of Melanosome Export. Biomedicines 2020; 8:biomedicines8100411. [PMID: 33066033 PMCID: PMC7601524 DOI: 10.3390/biomedicines8100411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/09/2020] [Accepted: 10/10/2020] [Indexed: 12/15/2022] Open
Abstract
CMT-308 is a nonantimicrobial chemically-modified tetracycline (CMT), which we have previously shown exhibits antifungal activity and pleiotropic anti-inflammatory activities, including inhibition of the enzymatic activity of matrix metalloproteinases (MMPs). Based on its chemical structure, we hypothesized that CMT-308 could inhibit melanogenesis and might be a candidate for the treatment of skin hyperpigmentation disorders which occur due to unregulated melanin biosynthesis and/or transport. CMT-308 was first studied for any effects on activity of the enzyme tyrosinase in vitro using a purified preparation of mushroom tyrosinase; the mode of inhibition of the soluble fungal enzyme was evaluated by Lineweaver-Burk and Dixon plots as well as by non-linear least squares fitting. Next, the effects of CMT-308 were tested in mammalian cell cultures using B16F10 mouse melanoma cells and further validated in darkly-pigmented human melanocytes (HEMn-DP). Our results showed that micromolar concentrations of CMT-308 inhibited mushroom tyrosinase enzyme activity, using the first two substrates in the melanogenesis pathway (l-tyrosine and l-3,4-dihydroxyphenylalanine (l-DOPA)); CMT-308 inhibited mushroom tyrosinase primarily via a mixed mode of inhibition, with the major contribution from a competitive mode. In B16F10 cell cultures, CMT-308 (10 µM) significantly diminished total melanin levels with a selective reduction of extracellular melanin levels, under both basal and hormone-stimulated conditions without any cytotoxicity over a duration of 72 h. Studies of potential mechanisms of inhibition of melanogenesis in B16F10 cells showed that, in mammalian cells, CMT-308 did not inhibit intracellular tyrosinase activity or the activity of α-glucosidase, an enzyme that regulates maturation of tyrosinase. However, CMT-308 suppressed MITF protein expression in B16F10 cells and showed copper chelating activity and antioxidant activity in a cell-free system. The significantly lower extracellular melanin levels obtained at 10 µM indicate that CMT-308’s anti-melanogenic action may be attributed to a selective inhibition of melanosome export with the perinuclear aggregation of melanosomes, rather than a direct effect on the tyrosinase-catalyzed steps in melanin biosynthesis. These results were validated in HEMn-DP cells where CMT-308 suppressed dendricity in a fully reversible manner without affecting intracellular melanin synthesis. Furthermore, the capacity of CMT-308 to inhibit melanosome export was retained in cocultures of HEMn-DP and HaCaT. In summary, our results offer promise for therapeutic strategies to combat the effects of hyperpigmentation by use of CMT-308 at low micromolar concentrations.
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Abstract
Myosins constitute a superfamily of actin-based molecular motor proteins that mediates a variety of cellular activities including muscle contraction, cell migration, intracellular transport, the formation of membrane projections, cell adhesion, and cell signaling. The 12 myosin classes that are expressed in humans share sequence similarities especially in the N-terminal motor domain; however, their enzymatic activities, regulation, ability to dimerize, binding partners, and cellular functions differ. It is becoming increasingly apparent that defects in myosins are associated with diseases including cardiomyopathies, colitis, glomerulosclerosis, neurological defects, cancer, blindness, and deafness. Here, we review the current state of knowledge regarding myosins and disease.
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8
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Jiang M, Paniagua AE, Volland S, Wang H, Balaji A, Li DG, Lopes VS, Burgess BL, Williams DS. Microtubule motor transport in the delivery of melanosomes to the actin-rich apical domain of the retinal pigment epithelium. J Cell Sci 2020; 133:jcs242214. [PMID: 32661088 PMCID: PMC7420818 DOI: 10.1242/jcs.242214] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 06/25/2020] [Indexed: 12/20/2022] Open
Abstract
Melanosomes are motile, light-absorbing organelles that are present in pigment cells of the skin and eye. It has been proposed that melanosome localization, in both skin melanocytes and the retinal pigment epithelium (RPE), involves melanosome capture from microtubule motors by an unconventional myosin, which dynamically tethers the melanosomes to actin filaments. Recent studies with melanocytes have questioned this cooperative capture model. Here, we test the model in RPE cells by imaging melanosomes associated with labeled actin filaments and microtubules, and by investigating the roles of different motor proteins. We found that a deficiency in cytoplasmic dynein phenocopies the lack of myosin-7a, in that melanosomes undergo fewer of the slow myosin-7a-dependent movements and are absent from the RPE apical domain. These results indicate that microtubule-based motility is required for the delivery of melanosomes to the actin-rich apical domain and support a capture mechanism that involves both microtubule and actin motors.
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Affiliation(s)
- Mei Jiang
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Antonio E Paniagua
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stefanie Volland
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Hongxing Wang
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Adarsh Balaji
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - David G Li
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Vanda S Lopes
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Barry L Burgess
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - David S Williams
- Departments of Ophthalmology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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9
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Alzahofi N, Welz T, Robinson CL, Page EL, Briggs DA, Stainthorp AK, Reekes J, Elbe DA, Straub F, Kallemeijn WW, Tate EW, Goff PS, Sviderskaya EV, Cantero M, Montoliu L, Nedelec F, Miles AK, Bailly M, Kerkhoff E, Hume AN. Rab27a co-ordinates actin-dependent transport by controlling organelle-associated motors and track assembly proteins. Nat Commun 2020; 11:3495. [PMID: 32661310 PMCID: PMC7359353 DOI: 10.1038/s41467-020-17212-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 06/04/2020] [Indexed: 11/09/2022] Open
Abstract
Cell biologists generally consider that microtubules and actin play complementary roles in long- and short-distance transport in animal cells. On the contrary, using melanosomes of melanocytes as a model, we recently discovered that the motor protein myosin-Va works with dynamic actin tracks to drive long-range organelle dispersion in opposition to microtubules. This suggests that in animals, as in yeast and plants, myosin/actin can drive long-range transport. Here, we show that the SPIRE-type actin nucleators (predominantly SPIRE1) are Rab27a effectors that co-operate with formin-1 to generate actin tracks required for myosin-Va-dependent transport in melanocytes. Thus, in addition to melanophilin/myosin-Va, Rab27a can recruit SPIREs to melanosomes, thereby integrating motor and track assembly activity at the organelle membrane. Based on this, we suggest a model in which organelles and force generators (motors and track assemblers) are linked, forming an organelle-based, cell-wide network that allows their collective activity to rapidly disperse the population of organelles long-distance throughout the cytoplasm.
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Affiliation(s)
- Noura Alzahofi
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Tobias Welz
- University Hospital Regensburg, Regensburg, Germany
| | | | - Emma L Page
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Amy K Stainthorp
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - James Reekes
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - David A Elbe
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Felix Straub
- University Hospital Regensburg, Regensburg, Germany
| | - Wouter W Kallemeijn
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, W12 0BZ, UK
| | - Edward W Tate
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, W12 0BZ, UK
| | - Philip S Goff
- Cell Biology and Genetics Research Centre, St. George's, University of London, London, SW17 0RE, UK
| | - Elena V Sviderskaya
- Cell Biology and Genetics Research Centre, St. George's, University of London, London, SW17 0RE, UK
| | - Marta Cantero
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid, 28049, Spain
- CIBERER-ISCIII, Madrid, Spain
| | - Lluis Montoliu
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid, 28049, Spain
- CIBERER-ISCIII, Madrid, Spain
| | - Francois Nedelec
- Sainsbury Laboratory, Cambridge University, Cambridge, CB2 1LR, UK
| | - Amanda K Miles
- John van Geest Cancer Research Centre, Nottingham Trent University, Nottingham, NG11 8NS, UK
| | - Maryse Bailly
- UCL Institute of Ophthalmology, 11-43 Bath St, London, EC1V 9EL, UK
| | | | - Alistair N Hume
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK.
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Jo CS, Park HI, Jung HJ, Park JI, Lee JE, Myung CH, Hwang JS. A novel function of Prohibitin on melanosome transport in melanocytes. Theranostics 2020; 10:3880-3891. [PMID: 32226526 PMCID: PMC7086355 DOI: 10.7150/thno.41383] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/13/2020] [Indexed: 01/26/2023] Open
Abstract
Prohibitin (PHB, also known as PHB1 or BAP32), is a highly conserved 31kDa protein that expressed in many cellular compartments, such as mitochondria, nucleus, cytosol, and plasma membrane, and plays roles in regulating the transcription of genes, apoptosis, and mitochondrial biogenesis. There is a report that Prohibitin expression is required for the stimulation of pigmentation by melanogenin. However, no studies have been published on the function of PHB in melanocytes, especially in melanosome transport. Methods: Immunofluorescence was performed to confirm the localization of PHB. siRNA transfections, Co-immunoprecipitation, western blotting and proximity ligation assay were performed to find binding state between proteins and demonstrate functions of PHB on melanosome transport. Results: PHB is located in the melanosome and perinuclear aggregation of melanosome is induced when expression of PHB is reduced with no influence on melanin contents. PHB binds directly to Rab27a and Mlph but not Myosin-Va. Rab27a and Mlph bind to specific domains of PHB. Reduced expression of PHB led to the impaired binding affinity between Rab27a and Mlph. Conclusion: PHB regulates melanosome transport by linking to Rab27a and Mlph in melanocytes. Targeting and regulating PHB not only manages pigmentation in melanocytes, but also controls hyperpigmentation in melanoma
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Myosin Va and spermine synthase: partners in exosome transport. Biosci Rep 2019; 39:BSR20190326. [PMID: 30967493 PMCID: PMC6488853 DOI: 10.1042/bsr20190326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 11/21/2022] Open
Abstract
A recent paper in Bioscience Reports (BSR20182189) describes the discovery of an
interaction between the motor protein myosin Va and the metabolic enzyme
spermine synthase. Myosin Va is a molecular motor which plays a key role in
vesicle transport. Mutations in the gene which encodes this protein are
associated with Griscelli syndrome type 1 and the ‘dilute’
phenotype in animals. Spermine synthase catalyzes the conversion of spermidine
to spermine. This largely cytoplasmic enzyme can also be localized to the
soluble fraction in exosomes. Mutations in the spermine synthase gene are
associated with Snyder Robinson mental retardation syndrome. The interaction
between the two proteins was detected using the yeast two hybrid method and
verified by microscale thermophoresis of recombinant proteins. Knockdown of the
MYO5A gene reduced the expression of mRNA coding for
spermine synthase. The amount of this transcript was also reduced in cells
derived from a patient with Griscelli syndrome type 1. This suggests that, in
addition to a direct physical interaction between the two proteins, myosin Va
also modulates the transcription of the spermine synthase gene. The mechanism
for this modulation is currently unknown. These findings have implications for
Griscelli syndrome type 1 and Snyder Robinson mental retardation syndrome. They
also suggest that interactions between myosin Va and soluble exosome proteins
such as spermine synthase may be important in the mechanism of exosome
transport.
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12
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Myosin Va from Eriocheir sinensis: cDNA cloning, expression and involvement in growth and development. Comp Biochem Physiol B Biochem Mol Biol 2018; 226:45-52. [PMID: 30138681 DOI: 10.1016/j.cbpb.2018.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 07/16/2018] [Accepted: 08/13/2018] [Indexed: 11/23/2022]
Abstract
Myosin Va, a member of the myosin superfamily, has been widely identified associated with processes of cellular motility, which include neurotransmitter release and synaptic plasticity during neurodevelopment. However, the function of myosin Va in the growth and development of crustaceans has not yet been reported. In this study, a full-length cDNA of myosin Va (named as EsMyoVa) was cloned from the Chinese mitten crab, Eriocheir sinensis, and the expression patterns were detected in different tissues and larval developmental stages. The full-length cDNA of EsMyoVa was 6037 bp in length. Real time quantitative reverse transcription PCR (qRT-PCR) analysis showed that EsMyoVa transcript has a wide tissue distribution pattern and is expressed in zoeae, megalopa, juvenile crab stages and adults. In order to further study the function of this gene, we used RNAi technology in the muscle, hepatopancreas, gill, and gonad. After double-stranded RNA (dsRNA) injection, the expression level of EsMyoVa was significantly decreased in all tissues in both sexes and the gene knockdown effects of dsRNA persisted for at least 6 days. Subsequently, the role of EsMyoVa was revealed by silencing the transcript through one month injections of Myosin Va dsRNA. Crabs with reduced levels of EsMyoVa transcripts displayed a dramatic slowing in growth rate and considerably higher mortality compared to control groups, which indicated that this gene had important role of regulating growth and development.
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Li YR, Yang WX. Myosins as fundamental components during tumorigenesis: diverse and indispensable. Oncotarget 2018; 7:46785-46812. [PMID: 27121062 PMCID: PMC5216836 DOI: 10.18632/oncotarget.8800] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 04/10/2016] [Indexed: 12/11/2022] Open
Abstract
Myosin is a kind of actin-based motor protein. As the crucial functions of myosin during tumorigenesis have become increasingly apparent, the profile of myosin in the field of cancer research has also been growing. Eighteen distinct classes of myosins have been discovered in the past twenty years and constitute a diverse superfamily. Various myosins share similar structures. They all convert energy from ATP hydrolysis to exert mechanical stress upon interactions with microfilaments. Ongoing research is increasingly suggesting that at least seven kinds of myosins participate in the formation and development of cancer. Myosins play essential roles in cytokinesis failure, chromosomal and centrosomal amplification, multipolar spindle formation and DNA microsatellite instability. These are all prerequisites of tumor formation. Subsequently, myosins activate various processes of tumor invasion and metastasis development including cell migration, adhesion, protrusion formation, loss of cell polarity and suppression of apoptosis. In this review, we summarize the current understanding of the roles of myosins during tumorigenesis and discuss the factors and mechanisms which may regulate myosins in tumor progression. Furthermore, we put forward a completely new concept of “chromomyosin” to demonstrate the pivotal functions of myosins during karyokinesis and how this acts to optimize the functions of the members of the myosin superfamily.
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Affiliation(s)
- Yan-Ruide Li
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou, China
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14
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Park EH, Bae WY, Kim JY, Kim KT, Paik HD. Antimelanogenic effects of Inula britannica flower petal extract fermented by Lactobacillus plantarum KCCM 11613P *. J Zhejiang Univ Sci B 2017; 18:816-824. [PMCID: PMC5611553 DOI: 10.1631/jzus.b1600234] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 10/23/2016] [Indexed: 07/30/2023]
Abstract
The inhibitory effects of Lactobacillus plantarum-fermented and non-fermented Inula britannica extracts on the tyrosinase activity were comparatively investigated to examine whether and how they improve the whitening activity, and the contents of total flavonoids and polyphenolics as bioactive compounds were determined. The skin whitening activity using in vitro or ex vivo tyrosinase and L-3,4-dihydroxyphenylalanine (L-DOPA) staining was examined. The total flavonoid content (TFC) was increased by 13.4% after 72 h-fermentation. The viabilities of the B16F10 cells treated with the fermented and non-fermented control extracts were 100.26% and 92.15% at 500 µg/ml, respectively. In addition, the inhibition of tyrosinase activity was increased by the fermented samples from 29.33% to 41.74% following fermentation for up to 72 h. The tyrosinase activity of the untreated control group was increased to 145.69% in B16F10 cells. The results showed that I. britannica fermented by L. plantarum dose-dependently inhibited tyrosinase activity, which was stimulated by α-melanocyte stimulating hormone. These results suggest that lactic fermented I. britannica extracts can be used as effective skin-whitening materials.
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Affiliation(s)
- Eun-hye Park
- Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 05029, Korea
| | - Won-young Bae
- Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 05029, Korea
| | - Jae-yeon Kim
- Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 05029, Korea
| | - Kee-tae Kim
- Bio/Molecular Informatics Center, Konkuk University, Seoul 05029, Korea
| | - Hyun-dong Paik
- Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 05029, Korea
- Bio/Molecular Informatics Center, Konkuk University, Seoul 05029, Korea
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15
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Crossley VJ, Debnath A, Chang YM, Fowkes RC, Elliott J, Syme HM. Breed, Coat Color, and Hair Length as Risk Factors for Hyperthyroidism in Cats. J Vet Intern Med 2017; 31:1028-1034. [PMID: 28612380 PMCID: PMC5508346 DOI: 10.1111/jvim.14737] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 02/28/2017] [Accepted: 04/11/2017] [Indexed: 12/19/2022] Open
Abstract
Background Hyperthyroidism is very common in older cats, but the etiopathogenesis is poorly understood. Decreased risk of hyperthyroidism has been reported in certain colorpoint breeds, and this observation previously has been hypothesized to result from relatively greater tyrosine availability for thyroid hormone production because of limited ability to convert tyrosine to melanin pigment. However, studies investigating a potential link between coat pigmentation and risk of hyperthyroidism are limited. Objective To identify associations between coat phenotype and hyperthyroidism by investigation of breed, coat color, and hair length as risk factors for the disease. Animals Data were used from 4,705 cats aged ≥10 years, referred to a single veterinary teaching hospital (2006–2014) in the United Kingdom. Methods Retrospective, epidemiological, cross‐sectional study using Bayesian multivariable logistic regression to assess risk factors for hyperthyroidism. Results Burmese (odds ratio [OR], 0.01; 0.00–0.23; P = .004), Tonkinese (OR, 0.05; 0.00–0.95; P = .046), Persian (OR, 0.21; 0.10–0.44; P < .001), Siamese (OR, 0.27; 0.12–0.61; P = .002), Abyssinian (OR, 0.04; 0.00–0.74; P = .031), and British shorthair (OR, 0.47; 0.28–0.79; P = .004) breeds had decreased risk of hyperthyroidism compared to domestic shorthairs. Longhaired, nonpurebred cats (OR, 1.30; 1.03–1.64; P = .028) were at increased risk of hyperthyroidism. Coat color/pattern was not associated with hyperthyroidism in nonpurebred cats. Conclusions and Clinical Importance We identified decreased risk of hyperthyroidism in the Tonkinese, Abyssinian, and British shorthair breeds, identified an association between risk of hyperthyroidism and hair length, and confirmed decreased risk in Burmese, Siamese, and Persian breeds. Additional studies are warranted to further investigate these findings.
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Affiliation(s)
- V J Crossley
- Department of Clinical Science and Services, Royal Veterinary College, University of London, London, UK
| | - A Debnath
- Department of Clinical Science and Services, Royal Veterinary College, University of London, London, UK
| | - Y M Chang
- Research Support Office, Royal Veterinary College, University of London, London, UK
| | - R C Fowkes
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - J Elliott
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - H M Syme
- Department of Clinical Science and Services, Royal Veterinary College, University of London, London, UK
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16
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Myosin Va's adaptor protein melanophilin enforces track selection on the microtubule and actin networks in vitro. Proc Natl Acad Sci U S A 2017; 114:E4714-E4723. [PMID: 28559319 DOI: 10.1073/pnas.1619473114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pigment organelles, or melanosomes, are transported by kinesin, dynein, and myosin motors. As such, melanosome transport is an excellent model system to study the functional relationship between the microtubule- and actin-based transport systems. In mammalian melanocytes, it is well known that the Rab27a/melanophilin/myosin Va complex mediates actin-based transport in vivo. However, pathways that regulate the overall directionality of melanosomes on the actin/microtubule networks have not yet been delineated. Here, we investigated the role of PKA-dependent phosphorylation on the activity of the actin-based Rab27a/melanophilin/myosin Va transport complex in vitro. We found that melanophilin, specifically its C-terminal actin-binding domain (ABD), is a target of PKA. Notably, in vitro phosphorylation of the ABD closely recapitulated the previously described in vivo phosphorylation pattern. Unexpectedly, we found that phosphorylation of the ABD affected neither the interaction of the complex with actin nor its movement along actin tracks. Surprisingly, the phosphorylation state of melanophilin was instead important for reversible association with microtubules in vitro. Dephosphorylated melanophilin preferred binding to microtubules even in the presence of actin, whereas phosphorylated melanophilin associated with actin. Indeed, when actin and microtubules were present simultaneously, melanophilin's phosphorylation state enforced track selection of the Rab27a/melanophilin/myosin Va transport complex. Collectively, our results unmasked the regulatory dominance of the melanophilin adaptor protein over its associated motor and offer an unexpected mechanism by which filaments of the cytoskeletal network compete for the moving organelles to accomplish directional transport on the cytoskeleton in vivo.
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17
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Robinson CL, Evans RD, Briggs DA, Ramalho JS, Hume AN. Inefficient recruitment of kinesin-1 to melanosomes precludes it from facilitating their transport. J Cell Sci 2017; 130:2056-2065. [PMID: 28490438 PMCID: PMC5482976 DOI: 10.1242/jcs.186064] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/03/2017] [Indexed: 12/25/2022] Open
Abstract
Microtubules and F-actin, and their associated motor proteins, are considered to play complementary roles in long- and short-range organelle transport. However, there is growing appreciation that myosin/F-actin networks can drive long-range transport. In melanocytes, myosin-Va and kinesin-1 have both been proposed as long-range centrifugal transporters moving melanosomes into the peripheral dendrites. Here, we investigated the role of kinesin-1 heavy chain (Kif5b) and its suggested targeting factor Rab1a in transport. We performed confocal microscopy and subcellular fractionation, but did not detect Kif5b or Rab1a on melanosomes. Meanwhile functional studies, using siRNA knockdown and dominant negative mutants, did not support a role for Kif5b or Rab1a in melanosome transport. To probe the potential of Kif5b to function in transport, we generated fusion proteins that target active Kif5b to melanosomes and tested their ability to rescue perinuclear clustering in myosin-Va-deficient cells. Expression of these chimeras, but not full-length Kif5b, dispersed melanosomes with similar efficiency to myosin-Va. Our data indicate that kinesin and microtubules can compensate for defects in myosin-Va and actin-based transport in mammals, but that endogenous Kif5b does not have an important role in transport of melanocytes due to its inefficient recruitment to melanosomes. Highlighted Article: We show that Kif5b can compensate for defects in myosin-Va-based transport in mammals, but that endogenous Kif5b plays a minimal role in transport in melanocytes due to inefficient recruitment to melanosomes.
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Affiliation(s)
| | - Richard D Evans
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Jose S Ramalho
- CEDOC Faculdade de Ciencias Medicas, Universidade Nova de Lisboa, 1169-056 Lisbon, Portugal
| | - Alistair N Hume
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
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18
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Wessels D, Lusche DF, Voss E, Kuhl S, Buchele EC, Klemme MR, Russell KB, Ambrose J, Soll BA, Bossler A, Milhem M, Goldman C, Soll DR. Melanoma cells undergo aggressive coalescence in a 3D Matrigel model that is repressed by anti-CD44. PLoS One 2017; 12:e0173400. [PMID: 28264026 PMCID: PMC5338862 DOI: 10.1371/journal.pone.0173400] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/20/2017] [Indexed: 12/29/2022] Open
Abstract
Using unique computer-assisted 3D reconstruction software, it was previously demonstrated that tumorigenic cell lines derived from breast tumors, when seeded in a 3D Matrigel model, grew as clonal aggregates which, after approximately 100 hours, underwent coalescence mediated by specialized cells, eventually forming a highly structured large spheroid. Non-tumorigenic cells did not undergo coalescence. Because histological sections of melanomas forming in patients suggest that melanoma cells migrate and coalesce to form tumors, we tested whether they also underwent coalescence in a 3D Matrigel model. Melanoma cells exiting fragments of three independent melanomas or from secondary cultures derived from them, and cells from the melanoma line HTB-66, all underwent coalescence mediated by specialized cells in the 3D model. Normal melanocytes did not. However, coalescence of melanoma cells differed from that of breast-derived tumorigenic cell lines in that they 1) coalesced immediately, 2) underwent coalescence as individual cells as well as aggregates, 3) underwent coalescence far faster and 4) ultimately formed long, flat, fenestrated aggregates that were extremely dynamic. A screen of 51 purified monoclonal antibodies (mAbs) targeting cell surface-associated molecules revealed that two mAbs, anti-beta 1 integrin/(CD29) and anti-CD44, blocked melanoma cell coalescence. They also blocked coalescence of tumorigenic cells derived from a breast tumor. These results add weight to the commonality of coalescence as a characteristic of tumorigenic cells, as well as the usefulness of the 3D Matrigel model and software for both investigating the mechanisms regulating tumorigenesis and screening for potential anti-tumorigenesis mAbs.
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Affiliation(s)
- Deborah Wessels
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Daniel F. Lusche
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Edward Voss
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Spencer Kuhl
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Emma C. Buchele
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Michael R. Klemme
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Kanoe B. Russell
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Joseph Ambrose
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Benjamin A. Soll
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
| | - Aaron Bossler
- Department of Molecular Pathology, University of Iowa Hospitals and Clinics, Iowa City, IA United States of America
| | - Mohammed Milhem
- Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA United States of America
| | - Charles Goldman
- Mercy Hospital System of Des Moines, Des Moines, IA United States of America
| | - David R. Soll
- Developmental Studies Hybridoma Bank, Department of Biology, University of Iowa, Iowa City, IA United States of America
- * E-mail:
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19
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Tyrosinase Depletion Prevents the Maturation of Melanosomes in the Mouse Hair Follicle. PLoS One 2015; 10:e0143702. [PMID: 26619124 PMCID: PMC4664286 DOI: 10.1371/journal.pone.0143702] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/08/2015] [Indexed: 01/21/2023] Open
Abstract
The mechanisms that lead to variation in human skin and hair color are not fully understood. To better understand the molecular control of skin and hair color variation, we modulated the expression of Tyrosinase (Tyr), which controls the rate-limiting step of melanogenesis, by expressing a single-copy, tetracycline-inducible shRNA against Tyr in mice. Moderate depletion of TYR was sufficient to alter the appearance of the mouse coat in black, agouti, and yellow coat color backgrounds, even though TYR depletion did not significantly inhibit accumulation of melanin within the mouse hair. Ultra-structural studies revealed that the reduction of Tyr inhibited the accumulation of terminal melanosomes, and inhibited the expression of genes that regulate melanogenesis. These results indicate that color in skin and hair is determined not only by the total amount of melanin within the hair, but also by the relative accumulation of mature melanosomes.
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20
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Bultema JJ, Boyle JA, Malenke PB, Martin FE, Dell'Angelica EC, Cheney RE, Di Pietro SM. Myosin vc interacts with Rab32 and Rab38 proteins and works in the biogenesis and secretion of melanosomes. J Biol Chem 2014; 289:33513-28. [PMID: 25324551 DOI: 10.1074/jbc.m114.578948] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Class V myosins are actin-based motors with conserved functions in vesicle and organelle trafficking. Herein we report the discovery of a function for Myosin Vc in melanosome biogenesis as an effector of melanosome-associated Rab GTPases. We isolated Myosin Vc in a yeast two-hybrid screening for proteins that interact with Rab38, a Rab protein involved in the biogenesis of melanosomes and other lysosome-related organelles. Rab38 and its close homolog Rab32 bind to Myosin Vc but not to Myosin Va or Myosin Vb. Binding depends on residues in the switch II region of Rab32 and Rab38 and regions of the Myosin Vc coiled-coil tail domain. Myosin Vc also interacts with Rab7a and Rab8a but not with Rab11, Rab17, and Rab27. Although Myosin Vc is not particularly abundant on pigmented melanosomes, its knockdown in MNT-1 melanocytes caused defects in the trafficking of integral membrane proteins to melanosomes with substantially increased surface expression of Tyrp1, nearly complete loss of Tyrp2, and significant Vamp7 mislocalization. Knockdown of Myosin Vc in MNT-1 cells more than doubled the abundance of pigmented melanosomes but did not change the number of unpigmented melanosomes. Together the data demonstrate a novel role for Myosin Vc in melanosome biogenesis and secretion.
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Affiliation(s)
- Jarred J Bultema
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, the Department of Chemistry and Biochemistry, University of Colorado, Colorado Springs, Colorado Springs, Colorado 80918
| | - Judith A Boyle
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Parker B Malenke
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Faye E Martin
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Esteban C Dell'Angelica
- the Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095, and
| | - Richard E Cheney
- the Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Santiago M Di Pietro
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523,
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21
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Joung JY, Lee HY, Park J, Lee JY, Chang BH, No KT, Nam KY, Hwang JS. Identification of novel rab27a/melanophilin blockers by pharmacophore-based virtual screening. Appl Biochem Biotechnol 2013; 172:1882-97. [PMID: 24293275 DOI: 10.1007/s12010-013-0615-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 10/30/2013] [Indexed: 12/31/2022]
Abstract
Melanocytes are unique cells that produce specific melanin-containing intracellular organelles called melanosomes. Melanosomes are transported from the perinuclear area of melanocytes toward the plasma membrane as they become more melanized in order to increase skin pigmentation. In this vesicular trafficking of melanosomes, Rab27a, melanophilin, and myosin Va play crucial roles in linking melanosomes to actin-based motors. To identify novel compounds to inhibit binding interface between Rab27a and melanophilin, a pharmacophore model was built based on a modeled 3D structure of the protein complex that describes the essential binding residues in the intermolecular interaction. A pharmacophore model was employed to screen a chemical library database. Finally, 25 virtual hits were selected for biological evaluations. The biological activities of 11 analogues were evaluated in a second assay. Two compounds were identified as having concentration-dependent inhibitory activity. By analyzing structure-activity relationships of derivatives of BMD-20, two hydroxyl functional groups were found to be critical for blocking the intermolecular binding between Rab27a and melanophilin.
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Affiliation(s)
- Jong Young Joung
- Bioinformatics and Molecular Design Research Center, Seoul, 120-749, Republic of Korea
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22
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Wei Z, Liu X, Yu C, Zhang M. Structural basis of cargo recognitions for class V myosins. Proc Natl Acad Sci U S A 2013. [PMID: 23798443 PMCID: PMC3710815 DOI: 10.1073/pnas.1306768110;] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023] Open
Abstract
Class V myosins (MyoV), the most studied unconventional myosins, recognize numerous cargos mainly via the motor's globular tail domain (GTD). Little is known regarding how MyoV-GTD recognizes such a diverse array of cargos specifically. Here, we solved the crystal structures of MyoVa-GTD in its apo-form and in complex with two distinct cargos, melanophilin and Rab interacting lysosomal protein-like 2. The apo-MyoVa-GTD structure indicates that most mutations found in patients with Griscelli syndrome, microvillus inclusion disease, or cancers or in "dilute" rodents likely impair the folding of GTD. The MyoVa-GTD/cargo complex structure reveals two distinct cargo-binding surfaces, one primarily via charge-charge interaction and the other mainly via hydrophobic interactions. Structural and biochemical analysis reveal the specific cargo-binding specificities of various isoforms of mammalian MyoV as well as very different cargo recognition mechanisms of MyoV between yeast and higher eukaryotes. The MyoVa-GTD structures resolved here provide a framework for future functional studies of vertebrate class V myosins.
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Affiliation(s)
- Zhiyi Wei
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, and
- Center of Systems Biology, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
- To whom correspondence may be addressed. E-mail: and
| | - Xiaotian Liu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, and
| | - Cong Yu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, and
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, and
- Center of Systems Biology, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
- To whom correspondence may be addressed. E-mail: and
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23
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Abstract
Class V myosins (MyoV), the most studied unconventional myosins, recognize numerous cargos mainly via the motor's globular tail domain (GTD). Little is known regarding how MyoV-GTD recognizes such a diverse array of cargos specifically. Here, we solved the crystal structures of MyoVa-GTD in its apo-form and in complex with two distinct cargos, melanophilin and Rab interacting lysosomal protein-like 2. The apo-MyoVa-GTD structure indicates that most mutations found in patients with Griscelli syndrome, microvillus inclusion disease, or cancers or in "dilute" rodents likely impair the folding of GTD. The MyoVa-GTD/cargo complex structure reveals two distinct cargo-binding surfaces, one primarily via charge-charge interaction and the other mainly via hydrophobic interactions. Structural and biochemical analysis reveal the specific cargo-binding specificities of various isoforms of mammalian MyoV as well as very different cargo recognition mechanisms of MyoV between yeast and higher eukaryotes. The MyoVa-GTD structures resolved here provide a framework for future functional studies of vertebrate class V myosins.
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24
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Seixas E, Barros M, Seabra MC, Barral DC. Rab and Arf proteins in genetic diseases. Traffic 2013; 14:871-85. [PMID: 23565987 DOI: 10.1111/tra.12072] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 04/03/2013] [Accepted: 04/08/2013] [Indexed: 01/29/2023]
Abstract
Rab and ADP-ribosylation factor (Arf) family proteins are master regulators of membrane trafficking and are involved in all steps of vesicular transport. These families of small guanine-nucleotide-binding (G) proteins are well suited to regulate membrane trafficking processes since their nucleotide state determines their conformation and the capacity to bind to a multitude of effectors, which mediate their functions. In recent years, several inherited diseases have been associated with mutations in genes encoding proteins belonging to these two families or in proteins that regulate their GTP-binding cycle. The genetic diseases that are caused by defects in Rabs, Arfs or their regulatory proteins are heterogeneous and display diverse symptoms. However, these diseases mainly affect two types of subcellular compartments, namely lysosome-related organelles and cilia. Also, several of these diseases affect the nervous system. Thus, the study of these diseases represents an opportunity to understand their etiology and the molecular mechanisms involved, as well as to develop novel therapeutic strategies.
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Affiliation(s)
- Elsa Seixas
- CEDOC, Faculdade de Ciências Médicas, FCM, Universidade Nova de Lisboa, 1169-056, Lisboa, Portugal
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25
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Neng L, Zhang W, Hassan A, Zemla M, Kachelmeier A, Fridberger A, Auer M, Shi X. Isolation and culture of endothelial cells, pericytes and perivascular resident macrophage-like melanocytes from the young mouse ear. Nat Protoc 2013; 8:709-20. [PMID: 23493068 DOI: 10.1038/nprot.2013.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This protocol describes a growth medium-based approach for obtaining cochlear endothelial cells (ECs), pericytes (PCs) and perivascular resident macrophage-like melanocytes (PVM/Ms) from the stria vascularis of mice aged between P10 and P15 (P, postnatal day). The procedure does not involve mechanical or enzymatic digestion of the sample tissue. Explants of stria vascularis, 'mini-chips', are selectively cultured in growth medium, and primary cell lines are obtained in 7-10 d. The method is simple and reliable, and it provides high-quality ECs, PVM/Ms and PCs with a purity >90% after two passages. This protocol is suitable for producing primary culture cells from organs and tissues of small volume and high anatomical complexity, such as the inner ear capillaries. The highly purified primary cell lines enable cell culture-based in vitro modeling of cell-cell interactions, barrier control function and drug action.
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Affiliation(s)
- Lingling Neng
- Oregon Hearing Research Center, Department of Otolaryngology/Head and Neck Surgery, Oregon Health & Science University, Portland, Oregon, USA
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26
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Insights into Stem Cell Factor chemotactic guidance of neural crest cells revealed by a real-time directionality-based assay. Eur J Cell Biol 2012; 91:375-90. [DOI: 10.1016/j.ejcb.2011.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 12/19/2011] [Accepted: 12/20/2011] [Indexed: 11/23/2022] Open
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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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28
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Hartman MA, Finan D, Sivaramakrishnan S, Spudich JA. Principles of unconventional myosin function and targeting. Annu Rev Cell Dev Biol 2011; 27:133-55. [PMID: 21639800 DOI: 10.1146/annurev-cellbio-100809-151502] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Unconventional myosins are a superfamily of actin-based motors implicated in diverse cellular processes. In recent years, much progress has been made in describing their biophysical properties, and headway has been made into analyzing their cellular functions. Here, we focus on the principles that guide in vivo motor function and targeting to specific cellular locations. Rather than describe each motor comprehensively, we outline the major themes that emerge from research across the superfamily and use specific examples to illustrate each. In presenting the data in this format, we seek to identify open questions in each field as well as to point out commonalities between them. To advance our understanding of myosins' roles in vivo, clearly we must identify their cellular cargoes and the protein complexes that regulate motor attachment to fully appreciate their functions on the cellular and developmental levels.
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Affiliation(s)
- M Amanda Hartman
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
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Abstract
Coat colors are determined by melanin (eumelanin and pheomelanin). Melanin is synthesized in melanocytes and accumulates in special organelles, melanosomes, which upon maturation are transferred to keratinocytes. Melanocytes differentiate from undifferentiated precursors, called melanoblasts, which are derived from neural crest cells. Melanoblast/melanocyte proliferation and differentiation are regulated by the tissue environment, especially by keratinocytes, which synthesize endothelins, steel factor, hepatocyte growth factor, leukemia inhibitory factor and granulocyte-macrophage colony-stimulating factor. Melanocyte differentiation is also stimulated by alpha-melanocyte stimulating hormone; in the mouse, however, this hormone is likely carried through the bloodstream and not produced locally in the skin. Melanoblast migration, proliferation and differentiation are also regulated by many coat color genes otherwise known for their ability to regulate melanosome formation and maturation, pigment type switching and melanosome distribution and transfer. Thus, melanocyte proliferation and differentiation are not only regulated by genes encoding typical growth factors and their receptors but also by genes classically known for their role in pigment formation.
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Affiliation(s)
- Tomohisa Hirobe
- Radiation Effect Mechanisms Research Group, National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba, Japan Graduate School of Science, Chiba University, Yayoi-cho, Inage-ku, Chiba, Japan.
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Xu X, Kedlaya R, Higuchi H, Ikeda S, Justice MJ, Setaluri V, Ikeda A. Mutation in archain 1, a subunit of COPI coatomer complex, causes diluted coat color and Purkinje cell degeneration. PLoS Genet 2010; 6:e1000956. [PMID: 20502676 PMCID: PMC2873907 DOI: 10.1371/journal.pgen.1000956] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 04/19/2010] [Indexed: 11/18/2022] Open
Abstract
Intracellular trafficking is critical for delivering molecules and organelles to their proper destinations to carry out normal cellular functions. Disruption of intracellular trafficking has been implicated in the pathogenesis of various neurodegenerative disorders. In addition, a number of genes involved in vesicle/organelle trafficking are also essential for pigmentation, and loss of those genes is often associated with mouse coat-color dilution and human hypopigmentary disorders. Hence, we postulated that screening for mouse mutants with both neurological defects and coat-color dilution will help identify additional factors associated with intracellular trafficking in neuronal cells. In this study, we characterized a mouse mutant with a unique N-ethyl-N-nitrosourea (ENU)-induced mutation, named nur17. nur17 mutant mice exhibit both coat-color dilution and ataxia due to Purkinje cell degeneration in the cerebellum. By positional cloning, we identified that the nur17 mouse carries a T-to-C missense mutation in archain 1 (Arcn1) gene which encodes the delta subunit of the coat protein I (COPI) complex required for intracellular trafficking. Consistent with this function, we found that intracellular trafficking is disrupted in nur17 melanocytes. Moreover, the nur17 mutation leads to common characteristics of neurodegenerative disorders such as abnormal protein accumulation, ER stress, and neurofibrillary tangles. Our study documents for the first time the physiological consequences of the impairment of the ARCN1 function in the whole animal and demonstrates a direct association between ARCN1 and neurodegeneration.
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Affiliation(s)
- Xinjie Xu
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Rajendra Kedlaya
- Department of Dermatology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Hitoshi Higuchi
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Sakae Ikeda
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Monica J. Justice
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Vijayasaradhi Setaluri
- Department of Dermatology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
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Lin KW, Fang S, Park J, Crews AL, Adler KB. MARCKS and related chaperones bind to unconventional myosin V isoforms in airway epithelial cells. Am J Respir Cell Mol Biol 2010; 43:131-6. [PMID: 20203291 DOI: 10.1165/rcmb.2010-0016rc] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We have shown previously that myristoylated alanine-rich C kinase substrate (MARCKS) is a key regulatory molecule in the process of mucin secretion by airway epithelial cells, and that part of the secretory mechanism involves intracellular associations of MARCKS with specific chaperones: heat shock protein 70 (Hsp70) and cysteine string protein (CSP). Here, we report that MARCKS also interacts with unconventional myosin isoforms within these cells, and further molecular interactions between MARCKS and these chaperones/cytoskeletal proteins are elucidated. Primary human bronchial epithelial cells and the HBE1 cell line both expressed myosin V and VI proteins, and both MARCKS and CSP were shown to bind to myosin V, specifically Va and Vc. This binding was enhanced by exposing the cells to phorbol-12-myristate-13-acetate, an activator of protein kinase C and stimulator of mucin secretion. Binding of MARCKS, Hsp70, and CSP was further investigated by His-tagged pull down assays of purified recombinant proteins and multiple transfections of HBE1 cells with fusion proteins (MARCKS-HA; Flag-Hsp70; c-Myc-CSP) and immunoprecipitation. The results showed that MARCKS binds directly to Hsp70, and that Hsp70 binds directly to CSP, but that MARCKS binding to CSP appears to require the presence of Hsp70. Interrelated binding(s) of MARCKS, chaperones, and unconventional myosin isoforms may be integral to the mucin secretion process.
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Affiliation(s)
- Ko-Wei Lin
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, 27606, USA
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32
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Ortolani-Machado C, Freitas P, Faraco C. Melanogenesis in dermal melanocytes of Japanese Silky chicken embryos. Tissue Cell 2009; 41:239-48. [DOI: 10.1016/j.tice.2008.11.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 11/21/2008] [Accepted: 11/27/2008] [Indexed: 10/21/2022]
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Woolner S, Bement WM. Unconventional myosins acting unconventionally. Trends Cell Biol 2009; 19:245-52. [PMID: 19406643 DOI: 10.1016/j.tcb.2009.03.003] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 03/26/2009] [Accepted: 03/27/2009] [Indexed: 11/26/2022]
Abstract
Unconventional myosins are proteins that bind actin filaments in an ATP-regulated manner. Because of their association with membranes, they have traditionally been viewed as motors that function primarily to transport membranous organelles along actin filaments. Recently, however, a wealth of roles for myosins that are not obviously related to organelle transport have been uncovered, including organization of F-actin, mitotic spindle regulation and gene transcription. Furthermore, it has also become apparent that the motor domains of different myosins vary strikingly in their biophysical attributes. We suggest that the assumption that most unconventional myosins function primarily as organelle transporters might be misguided.
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Affiliation(s)
- Sarah Woolner
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, UK.
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Röder IV, Petersen Y, Choi KR, Witzemann V, Hammer JA, Rudolf R. Role of Myosin Va in the plasticity of the vertebrate neuromuscular junction in vivo. PLoS One 2008; 3:e3871. [PMID: 19057648 PMCID: PMC2587709 DOI: 10.1371/journal.pone.0003871] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 11/10/2008] [Indexed: 01/07/2023] Open
Abstract
Background Myosin Va is a motor protein involved in vesicular transport and its absence leads to movement disorders in humans (Griscelli and Elejalde syndromes) and rodents (e.g. dilute lethal phenotype in mice). We examined the role of myosin Va in the postsynaptic plasticity of the vertebrate neuromuscular junction (NMJ). Methodology/Principal Findings Dilute lethal mice showed a good correlation between the propensity for seizures, and fragmentation and size reduction of NMJs. In an aneural C2C12 myoblast cell culture, expression of a dominant-negative fragment of myosin Va led to the accumulation of punctate structures containing the NMJ marker protein, rapsyn-GFP, in perinuclear clusters. In mouse hindlimb muscle, endogenous myosin Va co-precipitated with surface-exposed or internalised acetylcholine receptors and was markedly enriched in close proximity to the NMJ upon immunofluorescence. In vivo microscopy of exogenous full length myosin Va as well as a cargo-binding fragment of myosin Va showed localisation to the NMJ in wildtype mouse muscles. Furthermore, local interference with myosin Va function in live wildtype mouse muscles led to fragmentation and size reduction of NMJs, exclusion of rapsyn-GFP from NMJs, reduced persistence of acetylcholine receptors in NMJs and an increased amount of punctate structures bearing internalised NMJ proteins. Conclusions/Significance In summary, our data show a crucial role of myosin Va for the plasticity of live vertebrate neuromuscular junctions and suggest its involvement in the recycling of internalised acetylcholine receptors back to the postsynaptic membrane.
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Affiliation(s)
- Ira Verena Röder
- Institute of Toxicology and Genetics, Research Center Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Yvonne Petersen
- Institute of Toxicology and Genetics, Research Center Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Kyeong Rok Choi
- Institute of Toxicology and Genetics, Research Center Karlsruhe, Eggenstein-Leopoldshafen, Germany
| | - Veit Witzemann
- Max-Planck-Institute for Medical Research, Heidelberg, Germany
| | - John A. Hammer
- Laboratory of Cell Biology, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rüdiger Rudolf
- Institute of Toxicology and Genetics, Research Center Karlsruhe, Eggenstein-Leopoldshafen, Germany
- * E-mail:
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Pranchevicius MCS, Baqui MMA, Ishikawa-Ankerhold HC, Lourenço EV, Leão RM, Banzi SR, dos Santos CT, Roque-Barreira MC, Barreira MCR, Espreafico EM, Larson RE. Myosin Va phosphorylated on Ser1650 is found in nuclear speckles and redistributes to nucleoli upon inhibition of transcription. ACTA ACUST UNITED AC 2008; 65:441-56. [PMID: 18330901 DOI: 10.1002/cm.20269] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Nuclear actin and nuclear myosins have been implicated in the regulation of gene expression in vertebrate cells. Myosin V is a class of actin-based motor proteins involved in cytoplasmic vesicle transport and anchorage, spindle-pole alignment and mRNA translocation. In this study, myosin-Va, phosphorylated on a conserved serine in the tail domain (phospho-ser(1650) MVa), was localized to subnuclear compartments. A monoclonal antibody, 9E6, raised against a peptide corresponding to phosphoserine(1650) and flanking regions of the murine myosin Va sequence, was immunoreactive to myosin Va heavy chain in cellular and nuclear extracts of HeLa cells, PC12 cells and B16-F10 melanocytes. Immunofluorescence microscopy with this antibody revealed discrete irregular spots within the nucleoplasm that colocalized with SC35, a splicing factor that earmarks nuclear speckles. Phospho-ser(1650) MVa was not detected in other nuclear compartments, such as condensed chromatin, Cajal bodies, gems and perinucleolar caps. Although nucleoli also were not labeled by 9E6 under normal conditions, inhibition of transcription in HeLa cells by actinomycin D caused the redistribution of phospho-ser(1650) MVa to nucleoli, as well as separating a fraction of phospho-ser(1650) MVa from SC35 into near-neighboring particles. These observations indicate a novel role for myosin Va in nuclear compartmentalization and offer a new lead towards the understanding of actomyosin-based gene regulation.
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Affiliation(s)
- Maria Cristina S Pranchevicius
- Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Provance DW, Addison EJ, Wood PR, Chen DZ, Silan CM, Mercer JA. Myosin-Vb functions as a dynamic tether for peripheral endocytic compartments during transferrin trafficking. BMC Cell Biol 2008; 9:44. [PMID: 18687135 PMCID: PMC2533098 DOI: 10.1186/1471-2121-9-44] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 08/07/2008] [Indexed: 12/14/2022] Open
Abstract
Background Myosin-Vb has been shown to be involved in the recycling of diverse proteins in multiple cell types. Studies on transferrin trafficking in HeLa cells using a dominant-negative myosin-Vb tail fragment suggested that myosin-Vb was required for recycling from perinuclear compartments to the plasma membrane. However, chemical-genetic, dominant-negative experiments, in which myosin-Vb was specifically induced to bind to actin, suggested that the initial hypothesis was incorrect both in its site and mode of myosin-Vb action. Instead, the chemical-genetic data suggested that myosin-Vb functions in the actin-rich periphery as a dynamic tether on peripheral endosomes, retarding transferrin transport to perinuclear compartments. Results In this study, we employed both approaches, with the addition of overexpression of full-length wild-type myosin-Vb and switching the order of myosin-Vb inhibition and transferrin loading, to distinguish between these hypotheses. Overexpression of full-length myosin-Vb produced large peripheral endosomes. Chemical-genetic inhibition of myosin-Vb after loading with transferrin did not prevent movement of transferrin from perinuclear compartments; however, virtually all myosin-Vb-decorated particles, including those moving on microtubules, were halted by the inhibition. Overexpression of the myosin-Vb tail caused a less-peripheral distribution of early endosome antigen-1 (EEA1). Conclusion All results favored the peripheral dynamic tethering hypothesis.
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37
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Localization of myosin-Va in subpopulations of cells in rat endocrine organs. Cell Tissue Res 2008; 333:263-79. [PMID: 18568366 DOI: 10.1007/s00441-008-0630-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Accepted: 04/30/2008] [Indexed: 10/22/2022]
Abstract
Myosin-Va is a Ca(2+)/calmodulin-regulated unconventional myosin involved in the transport of vesicles, membranous organelles, and macromolecular complexes composed of proteins and mRNA. The cellular localization of myosin-Va has been described in great detail in several vertebrate cell types, including neurons, melanocytes, lymphocytes, auditory tissues, and a number of cultured cells. Here, we provide an immunohistochemical view of the tissue distribution of myosin-Va in the major endocrine organs. Myosin-Va is highly expressed in the pineal and pituitary glands and in specific cell populations of other endocrine glands, especially the parafollicular cells of the thyroid, the principal cells of the parathyroid, the islets of Langerhans of the pancreas, the chromaffin cells of the adrenal medulla, and a subpopulation of interstitial testicular cells. Weak to moderate staining has been detected in steroidogenic cells of the adrenal cortex, ovary, and Leydig cells. Myosin-Va has also been localized to non-endocrine cells, such as the germ cells of the seminiferous epithelium and maturing oocytes and in the intercalated ducts of the exocrine pancreas. These data provide the first systematic description of myosin-Va localization in the major endocrine organs of rat.
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38
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Salerno VP, Calliari A, Provance DW, Sotelo-Silveira JR, Sotelo JR, Mercer JA. Myosin-Va mediates RNA distribution in primary fibroblasts from multiple organs. ACTA ACUST UNITED AC 2008; 65:422-33. [PMID: 18357619 DOI: 10.1002/cm.20272] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Myosin-Va has been shown to have multiple functions in a variety of cell types, including a role in RNA transport in neurons. Using primary cultures of cells from organs of young dilute-lethal (Myo5a(d-l)/Myo5a(d-l)) null mutant mice and wild-type controls, we show that in some, but not all, tissues, RNA distribution is dramatically different in the homozygous null mutant cells. The dependence of RNA localization on myosin-Va correlates with the relative abundance of the brain-specific splicing pattern of the myosin-Va tail. We also show that myosin-Va is involved in RNA localization soon after synthesis, because the effects of its absence are diminished for RNAs that are more than 30 min old. Finally, we show that localization of beta-actin mRNA is significantly changed by the absence of myosin-Va. These results suggest that myosin-Va is involved in a transient transport or tethering function in the perinuclear region.
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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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40
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Eppinga RD, Peng IF, Lin JLC, Wu CF, Lin JJC. Opposite effects of overexpressed myosin Va or heavy meromyosin Va on vesicle distribution, cytoskeleton organization, and cell motility in nonmuscle cells. ACTA ACUST UNITED AC 2008; 65:197-215. [DOI: 10.1002/cm.20255] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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41
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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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Geething NC, Spudich JA. Identification of a minimal myosin Va binding site within an intrinsically unstructured domain of melanophilin. J Biol Chem 2007; 282:21518-28. [PMID: 17513864 DOI: 10.1074/jbc.m701932200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin V is a molecular motor that transports a variety of cellular cargo, including organelles, vesicles, and messenger RNA. The proper peripheral distribution of melanosomes, a dense pigment-containing organelle, is dependent on actin and the activity of myosin Va. The recruitment of myosin Va to the melanosome and proper transport of the melanosome requires melanophilin, which directly binds to myosin Va and is tethered to the melanosome membrane via Rab27a. Here we use highly purified proteins to demonstrate that the globular tail domain of myosin Va binds directly to an intrinsically unstructured domain of melanophilin. The myosin Va binding domain of melanophilin lacks stable secondary structure, and (1)H NMR measurements indicate that the protein is unfolded. This domain is extremely sensitive to mild proteolysis and has a hydrodynamic radius that is consistent with a random coil-like polypeptide. We show that myosin Va binding does not induce the global folding of melanophilin. Truncations of melanophilin were utilized to define a short peptide sequence (26 residues) within melanophilin that is critical for myosin Va binding. We demonstrate that a peptide corresponding to these residues binds directly to the globular tail domain with the same affinity as melanophilin. We discuss the possible implications of protein intrinsic disorder in recruitment and maintenance of myosin Va on melanosome membranes.
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Affiliation(s)
- Nathan C Geething
- Department of Biochemistry, Stanford University, Stanford, California 94041, USA
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43
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Abstract
Vertebrate myosin Va is a typical processive motor with high duty ratio. Recent studies have revealed that the actin-activated ATPase activity of the full-length myosin Va (M5aFull) is inhibited at a low [Ca(2+)], which is due to the formation of a folded conformation of M5aFull. To clarify the underlying inhibitory mechanism, we analyzed the actin-activated ATP hydrolysis mechanism of the M5aFull at the inhibited and the activated states, respectively. Marked differences were found in the hydrolysis, P(i) release, and ADP release steps between the activated and the inhibited states. The kinetic constants of these steps of the activated state were similar to those of the unregulated S1 construct, in which the rate-limiting step was the ADP release step. On the other hand, the P(i) release rate from acto-M5aFull was decreased in EGTA by >1,000-fold, which makes this step the rate-limiting step for the actin-activated ATP hydrolysis cycle of M5aFull. The ADP off rate from acto-M5aFull was decreased by approximately 10-fold, and the equilibrium between the prehydrolysis state and the post hydrolysis state was shifted toward the former state in the inhibited state of M5aFull. Because of these changes, M5aFull spends a majority of the ATP hydrolysis cycling time in the weak actin binding state. The present results indicate that M5aFull molecules at a low [Ca(2+)] is inhibited as a cargo transporter not only due to the decrease in the cross-bridge cycling rate but also due to the decrease in the duty ratio thus being dissociated from actin.
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Affiliation(s)
- Osamu Sato
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachueetts 01655, USA
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44
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Abstract
Alopecia, that is, lack of hair in any quantity, is a frequent complaint of pet owners. Although mostly acquired, rare congenital forms of alopecia exist that are associated with abnormalities in hair follicle morphogenesis. Congenital alopecias can result in changes in quality or quantity of hair follicles and the hair fibres produced by them. They vary in terms of clinical presentation and mode of inheritance. Histopathology is usually needed in order to differentiate between a reduced number of otherwise normal hair follicles and qualitative hair follicle abnormalities. Although our understanding of the molecular mechanisms that drive hair follicle morphogenesis in mice and humans has significantly increased during the last decade, still very little is known about congenital alopecias in domestic animals. Because of their rarity and the general lack of knowledge about their pathophysiology, classification of congenital alopecias in domestic animals is still unsatisfactory. This article reviews hair follicle morphogenesis and its most important molecular mechanisms, and it discusses the various forms of congenital alopecia occurring in domestic animals that have been described in the literature, differentiating between hair follicle aplasia, hair follicle dysplasia (i.e. defects associated with hair follicle development and defects associated with hair shaft formation), and neuroectodermal dysplasias, the latter involving the hair follicle pigmentary system.
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45
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Buttow NC, Espreafico EM, de Souza RR, Romano EB. Immunolocalization of myosin-V in the peribronchial, intrapulmonary peritracheal plexuses of the Wistar rat. J Neurosci Methods 2006; 152:274-7. [PMID: 16271276 DOI: 10.1016/j.jneumeth.2005.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 09/16/2005] [Accepted: 09/20/2005] [Indexed: 10/25/2022]
Abstract
The location of myosin-V in whole mount preparations of the peritracheal and intrapulmonary peribronchial plexuses of Wistar rats has been shown by using an affinity-purified antibody specific to the medial tail domain of myosin-V. Myosin-V immunostaining was intense in the peritracheal and intrapulmonary peribronchial plexuses, allowing the visualization of neuronal cell bodies and fibers. Knowledge of the cellular localization and function of this class of myosin is an important achievement, as it allows the study of these plexuses so as to clarify the importance of the complex mechanism responsible for the functioning of the airways.
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Affiliation(s)
- Nilza Cristina Buttow
- Departamento de Ciências Morfofisiológicas, Universidade Estadual de Maringá, Av. Colombo, 5790 Bloco H-79, CEP 87020-900, Maringá, PR, Brazil.
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46
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Abstract
Organelle inheritance is one of several processes that occur during cell division. Recent studies on yeast vacuole inheritance have indicated rules that probably apply to most organelle-inheritance pathways. They have uncovered a molecular mechanism for membrane-cargo transport that is partially conserved from yeast to humans. They have also shown that the transport complex, which is composed of a molecular motor and its receptor, regulates the destination and timing of vacuole movement and might coordinate organelle movement with several other organelle functions.
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Affiliation(s)
- Lois S Weisman
- Department of Cell and Developmental Biology and Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA.
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47
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Boyle RT, McNamara JC. Association of kinesin and myosin with pigment granules in crustacean chromatophores. ACTA ACUST UNITED AC 2006; 19:68-75. [PMID: 16420248 DOI: 10.1111/j.1600-0749.2005.00277.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chromatic adaptation in crustaceans results from the differential distribution of colored pigment granules within their chromatophores consequent to cell signaling by neurosecretory peptides. However, the force transducing, mechanochemical protein motors responsible for granule translocation, and their molecular mechanisms of action, are not well understood. The present study uses immunocytochemical techniques and a motility assay in vitro to demonstrate that protein motors from the kinesin and myosin superfamilies are stably associated with membrane-bounded pigment granules in the red, ovarian chromatophores of the freshwater, palaemonid shrimp, Macrobrachium olfersii. Monoclonal antibodies against conventional kinesin heavy chain, and an anti-myosin whole serum, labeled pigment-containing fragments prepared from homogenates of chromatophores with fully dispersed or aggregated pigments: this finding infers a permanent association between the protein motors and the pigment granules, and suggests that such motors may be regulated while bound to their cargos. The pigment aggregator appears to be a myosin since the anti-myosin whole serum attenuated hormonally triggered pigment aggregation in the motility assay in vitro, and induced pigment hyper-dispersion in some chromatophores. Western blots of the chromatophore-containing, ovarian tissue homogenate demonstrated protein bands consistent with myosin II and myosin XII, either of which may be the pigment aggregator. This study provides the first direct evidence for myosin and kinesin protein motors directly and stably associated with pigment granules in crustacean chromatophores, and may represent the first successful isolation of myosin class XII.
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Affiliation(s)
- Robert Tew Boyle
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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48
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Abstract
Small GTPases of the Rab family control timing of vesicle fusion. Fusion of two vesicles can only occur when they have been brought into close contact. Transport by microtubule- or actin-based motor proteins will facilitate this process in vivo. Ideally, transport and vesicle fusion are linked activities. Active, GTP-bound Rab proteins dock on specific compartments and are therefore perfect candidates to control transport of the different compartments. Recently, a number of Rab proteins were identified that control motor protein recruitment to their specific target membranes. By cycling through inactive and active states, Rab proteins are able to control motor protein-mediated transport and subsequent fusion of intracellular structures in both spatial and timed manners.
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Affiliation(s)
- Ingrid Jordens
- Department of Tumor Biology, Netherlands Cancer Institute, Amsterdam, Netherlands
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49
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Pashkova N, Catlett NL, Novak JL, Weisman LS. A point mutation in the cargo-binding domain of myosin V affects its interaction with multiple cargoes. EUKARYOTIC CELL 2005; 4:787-98. [PMID: 15821138 PMCID: PMC1087822 DOI: 10.1128/ec.4.4.787-798.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Class V myosins move diverse intracellular cargoes, which attach via interaction of cargo-specific proteins to the myosin V globular tail. The globular tail of the yeast myosin V, Myo2p, contains two structural and functional subdomains. Subdomain I binds to the vacuole-specific protein, Vac17p, while subdomain II likely binds to an as yet unidentified secretory vesicle-specific protein. All functions of Myo2p require the tight association of subdomains I and II, which suggests that binding of a cargo to one subdomain may inhibit cargo-binding to a second subdomain. Thus, two types of mutations are predicted to specifically affect a subset of Myo2p cargoes: first are mutations within a cargo-specific binding region; second are mutations that mimic the inhibited conformation of one of the subdomains. Here we analyze a point mutation in subdomain I, myo2-2(G1248D), which is likely to be this latter type of mutation. myo2-2 has no effect on secretory vesicle movement. The secretory vesicle binding site is in subdomain II. However, myo2-2 is impaired in several Myo2p-related functions. While subdomains I and II of myo2-2p tightly associate, there are measurable differences in the conformation of its globular tail. Based solely on the ability to restore vacuole inheritance, a set of intragenic suppressors of myo2-2 were identified. All suppressor mutations reside in subdomain I. Moreover, subdomain I and II interactions occurred in all suppressors, demonstrating the importance of subdomain I and II association for Myo2p function. Furthermore, 3 of the 10 suppressors globally restored all tested defects in myo2-2. This large proportion of global suppressors strongly suggests that myo2-2(G1248) causes a conformational change in subdomain I that simultaneously affects multiple cargoes.
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Affiliation(s)
- Natasha Pashkova
- Department of Biochemistry, The University of Iowa, Iowa City, Iowa 52242, USA
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Varadi A, Tsuboi T, Rutter GA. Myosin Va transports dense core secretory vesicles in pancreatic MIN6 beta-cells. Mol Biol Cell 2005; 16:2670-80. [PMID: 15788565 PMCID: PMC1142415 DOI: 10.1091/mbc.e04-11-1001] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Revised: 02/07/2005] [Accepted: 03/14/2005] [Indexed: 11/11/2022] Open
Abstract
The role of unconventional myosins in neuroendocrine cells is not fully understood, with involvement suggested in the movement of both secretory vesicles and mitochondria. Here, we demonstrate colocalization of myosin Va (MyoVa) with insulin in pancreatic beta-cells and show that MyoVa copurifies with insulin in density gradients and with the vesicle marker phogrin-enhanced green fluorescent protein upon fluorescence-activated sorting of vesicles. By contrast, MyoVa immunoreactivity was poorly colocalized with mitochondrial or other markers. Demonstrating an important role for MyoVa in the recruitment of secretory vesicles to the cell surface, a reduction of MyoVa protein levels achieved by RNA interference caused a significant decrease in glucose- or depolarization-stimulated insulin secretion. Similarly, expression of the dominant-negative-acting globular tail domain of MyoVa decreased by approximately 50% the number of vesicles docked at the plasma membrane and by 87% the number of depolarization-stimulated exocytotic events detected by total internal reflection fluorescence microscopy. We conclude that MyoVa-driven movements of vesicles along the cortical actin network are essential for the terminal stages of regulated exocytosis in beta-cells.
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Affiliation(s)
- Aniko Varadi
- Henry Wellcome Laboratories for Integrated Cell Signalling, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
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