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Lan Y, Zeng W, Wang Y, Dong X, Shen X, Gu Y, Zhang W, Lu H. Opsin 3 mediates UVA-induced keratinocyte supranuclear melanin cap formation. Commun Biol 2023; 6:238. [PMID: 36869204 PMCID: PMC9984416 DOI: 10.1038/s42003-023-04621-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 02/22/2023] [Indexed: 03/05/2023] Open
Abstract
Solar ultraviolet (UV) radiation-induced DNA damage is a major risk factor for skin cancer development. UV-induced redistribution of melanin near keratinocyte nuclei leads to the formation of a supranuclear cap, which acts as a natural sunscreen and protects DNA by absorbing and scattering UV radiation. However, the mechanism underlying the intracellular movement of melanin in nuclear capping is poorly understood. In this study, we found that OPN3 is an important photoreceptor in human epidermal keratinocytes and is critical for UVA-mediated supranuclear cap formation. OPN3 mediates supranuclear cap formation via the calcium-dependent G protein-coupled receptor signaling pathway and ultimately upregulates Dync1i1 and DCTN1 expression in human epidermal keratinocytes via activating calcium/CaMKII, CREB, and Akt signal transduction. Together, these results clarify the role of OPN3 in regulating melanin cap formation in human epidermal keratinocytes, greatly expanding our understanding of the phototransduction mechanisms involved in physiological function in skin keratinocytes.
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Affiliation(s)
- Yinghua Lan
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Wen Zeng
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Yu Wang
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Xian Dong
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Xiaoping Shen
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Yangguang Gu
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Wei Zhang
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Hongguang Lu
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China.
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Identification of DNAH6 mutations in infertile men with multiple morphological abnormalities of the sperm flagella. Sci Rep 2019; 9:15864. [PMID: 31676830 PMCID: PMC6825154 DOI: 10.1038/s41598-019-52436-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 10/15/2019] [Indexed: 11/24/2022] Open
Abstract
Male infertility due to spermatogenesis defects affects millions of men worldwide. However, the genetic etiology of the vast majority remains unclear. Here we describe three men with primary infertility due to multiple morphological abnormalities of the sperm flagella (MMAF) from two unrelated Han Chinese families. We performed whole-exome sequencing (WES) and Sanger sequencing on the proband of family 1, and found that he carried novel compound heterozygous missense mutations in dynein axonemal heavy chain 6 (DNAH6) that resulted in the substitution of a conserved amino acid residue and co-segregated with the MMAF phenotype in this family. Papanicolaou staining and transmission electron microscopy analysis revealed morphological and ultrastructural abnormalities in the sperm flagella in carriers of these genetic variants. Immunostaining experiments showed that DNAH6 was localized in the sperm tail. This is the first report identifying novel recessive mutations in DNAH6 as a cause of MMAF. These findings expand the spectrum of known MMAF mutations and phenotypes and provide information that can be useful for genetic and reproductive counseling of MMAF patients.
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Tikhonenko I, Irizarry K, Khodjakov A, Koonce MP. Organization of microtubule assemblies in Dictyostelium syncytia depends on the microtubule crosslinker, Ase1. Cell Mol Life Sci 2016; 73:859-68. [PMID: 26298292 PMCID: PMC4738076 DOI: 10.1007/s00018-015-2026-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/27/2015] [Accepted: 08/18/2015] [Indexed: 11/30/2022]
Abstract
It has long been known that the interphase microtubule (MT) array is a key cellular scaffold that provides structural support and directs organelle trafficking in eukaryotic cells. Although in animal cells, a combination of centrosome nucleating properties and polymer dynamics at the distal microtubule ends is generally sufficient to establish a radial, polar array of MTs, little is known about how effector proteins (motors and crosslinkers) are coordinated to produce the diversity of interphase MT array morphologies found in nature. This diversity is particularly important in multinucleated environments where multiple MT arrays must coexist and function. We initiate here a study to address the higher ordered coordination of multiple, independent MT arrays in a common cytoplasm. Deletion of a MT crosslinker of the MAP65/Ase1/PRC1 family disrupts the spatial integrity of multiple arrays in Dictyostelium discoideum, reducing the distance between centrosomes and increasing the intermingling of MTs with opposite polarity. This result, coupled with previous dynein disruptions suggest a robust mechanism by which interphase MT arrays can utilize motors and crosslinkers to sense their position and minimize overlap in a common cytoplasm.
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Affiliation(s)
- Irina Tikhonenko
- Division of Translational Medicine, NYS Department of Health, Wadsworth Center, Empire State Plaza, PO Box 509, Albany, NY, 12201-0509, USA
| | - Karen Irizarry
- Division of Translational Medicine, NYS Department of Health, Wadsworth Center, Empire State Plaza, PO Box 509, Albany, NY, 12201-0509, USA
| | - Alexey Khodjakov
- Division of Translational Medicine, NYS Department of Health, Wadsworth Center, Empire State Plaza, PO Box 509, Albany, NY, 12201-0509, USA
| | - Michael P Koonce
- Division of Translational Medicine, NYS Department of Health, Wadsworth Center, Empire State Plaza, PO Box 509, Albany, NY, 12201-0509, USA.
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Structural Change in the Dynein Stalk Region Associated with Two Different Affinities for the Microtubule. J Mol Biol 2015; 428:1886-96. [PMID: 26585405 DOI: 10.1016/j.jmb.2015.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/08/2015] [Accepted: 11/09/2015] [Indexed: 12/13/2022]
Abstract
Dynein is a large microtubule-based motor complex that requires tight coupling of intra-molecular ATP hydrolysis with the generation of mechanical force and track-binding activity. However, the microtubule-binding domain is structurally separated by about 15nm from the nucleotide-binding sites by a coiled-coil stalk. Thus, long-range two-way communication is necessary for coordination between the catalytic cycle of ATP hydrolysis and dynein's track-binding affinities. To investigate the structural changes that occur in the dynein stalk region to produce two different microtubule affinities, here we improve the resolution limit of the previously reported structure of the entire stalk region and we investigate structural changes in the dynein stalk and strut/buttress regions by comparing currently available X-ray structures. In the light of recent crystal structures, the basis of the transition from the low-affinity to the high-affinity coiled-coil registry is discussed. A concerted movement model previously reported by Carter and Vale is modified more specifically, and we proposed it as the open zipper model.
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A kinesin-mediated mechanism that couples centrosomes to nuclei. Cell Mol Life Sci 2012; 70:1285-96. [PMID: 23161062 DOI: 10.1007/s00018-012-1205-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 10/03/2012] [Accepted: 10/22/2012] [Indexed: 12/13/2022]
Abstract
The M-type kinesin isoform, Kif9, has recently been implicated in maintaining a physical connection between the centrosome and nucleus in Dictyostelium discoideum. However, the mechanism by which Kif9 functions to link these two organelles remains obscure. Here we demonstrate that the Kif9 protein is localized to the nuclear envelope and is concentrated in the region underlying the centrosome point of attachment. Nuclear anchorage appears mediated through a specialized transmembrane domain located in the carboxyl terminus. Kif9 interacts with microtubules in in vitro binding assays and effects an endwise depolymerization of the polymer. These results suggest a model whereby Kif9 is anchored to the nucleus and generates a pulling force that reels the centrosome up against the nucleus. This is a novel activity for a kinesin motor, one important for progression of cells into mitosis and to ensure centrosome-nuclear parity in a multinuclear environment.
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Samereier M, Meyer I, Koonce MP, Gräf R. Live cell-imaging techniques for analyses of microtubules in Dictyostelium. Methods Cell Biol 2010; 97:341-57. [PMID: 20719279 DOI: 10.1016/s0091-679x(10)97018-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Dictyostelium amoebae provide a popular model system for analyses of cell and cytoskeletal dynamics. Yet, the sensitivity of Dictyostelium cells to phototoxic effects, their rapid cell movement, and the extraordinary motility of their microtubule system are specific challenges for live cell imaging. The protocols outlined in this chapter are optimized to minimize these challenges, using Dictyostelium cells expressing green fluorescent tubulin or microtubule plus-end markers such as TACC. We describe suitable specimen preparations, treatments with microtubule-depolymerizing drugs, and applicable settings on wide-field and confocal microscopy systems for four-dimensional time-lapse and fluorescence recovery after photobleaching analyses of microtubule dynamics.
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Affiliation(s)
- Matthias Samereier
- Department of Cell Biology, Institut for Biochemistry and Biology, University of Potsdam, Potsdam-Golm 27708, Germany D-14476
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Ma S, Fey P, Chisholm RL. Molecular motors and membrane traffic in Dictyostelium. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1525:234-44. [PMID: 11257437 DOI: 10.1016/s0304-4165(01)00109-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phagocytosis and membrane traffic in general are largely dependent on the cytoskeleton and their associated molecular motors. The myosin family of motors, especially the unconventional myosins, interact with the actin cortex to facilitate the internalization of external materials during the early steps of phagocytosis. Members of the kinesin and dynein motor families, which mediate transport along microtubules (MTs), facilitate the intracellular processing of the internalized materials and the movement of membrane. Recent studies indicate that some unconventional myosins are also involved in membrane transport, and that the MT- and actin-dependent transport systems might interact with each other. Studies in Dictyostelium have led to the discovery of many motors involved in critical steps of phagocytosis and membrane transport. With the ease of genetic and biochemical approaches, the established functional analysis to test phagocytosis and vesicle transport, and the effort of the Dictyostelium cDNA and Genome Projects, Dictyostelium will continue to be a superb model system to study phagocytosis in particular and cytoskeleton and motors in general.
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Affiliation(s)
- S Ma
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, IL 60611, USA
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Pollock N, Koonce MP, de Hostos EL, Vale RD. In vitro microtubule-based organelle transport in wild-type Dictyostelium and cells overexpressing a truncated dynein heavy chain. CELL MOTILITY AND THE CYTOSKELETON 2000; 40:304-14. [PMID: 9678672 DOI: 10.1002/(sici)1097-0169(1998)40:3<304::aid-cm8>3.0.co;2-c] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The transport of vesicular organelles along microtubules has been well documented in a variety of systems, but the molecular mechanisms underlying this process are not well understood. We have developed a method for preparing extracts from Dictyostelium discoideum which supports high levels of bidirectional, microtubule-based vesicle transport in vitro. This organelle transport assay was also adapted to observe specifically the motility of vesicles in the endocytic pathway. Vesicle transport can be reconstituted by recombining a high-speed supernatant with KI-washed organelles, which do not move in the absence of supernatant. Furthermore, a microtubule affinity-purified motor fraction supports robust bidirectional movement of the salt-washed organelles. The plus and minus end-directed transport activities can be separated by exploiting differences in their affinities for microtubules in the presence of 0.3 M KCl. We also used our assay to examine organelle transport in a strain of Dictyostelium overexpressing a 380-kDa C-terminal fragment of the cytoplasmic dynein heavy chain, which displays an altered microtubule pattern (380-kDa cells; [Koonce and Samso, Mol. Biol. Cell 7:935-948, 1996]). We have found that the frequency and velocity of minus end-directed membrane organelle movements were significantly reduced in 380-kDa cells relative to wild-type cells, while the frequency and velocity of plus end-directed movements were equivalent in the two cell types. The 380-kDa C-terminal fragment cosedimented with membrane organelles, although its affinity was significantly lower than that of native dynein. An impaired membrane-microtubule interaction may be responsible for the altered microtubule patterns in the 380-kDa cells.
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Affiliation(s)
- N Pollock
- Department of Pharmacology, University of California San Francisco, 94143, USA
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Koonce MP, Knecht DA. Cytoplasmic dynein heavy chain is an essential gene product in Dictyostelium. CELL MOTILITY AND THE CYTOSKELETON 2000; 39:63-72. [PMID: 9453714 DOI: 10.1002/(sici)1097-0169(1998)39:1<63::aid-cm6>3.0.co;2-h] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We describe here three different approaches to perturb cytoplasmic dynein heavy chain (DHC) gene function in Dictyostelium: integration of a marker into the heavy chain coding sequence by homologous recombination to disrupt transcription, expression of antisense RNA to inhibit translation, and expression of a 158 kDa amino-terminal coding region to perturb the native protein organization. By homologous recombination, we fail to obtain cells that lack an intact DHC gene product. Cells containing antisense orientation plasmids (but not sense) appear to die 4 to 6 days following transformation. Plasmids designed to overexpress an amino-terminal region of the DHC result in substantially reduced transformation efficiency. When expressed at low levels, the truncated amino-terminal product appears capable of dimerizing with an intact heavy chain or with itself, essentially producing a cargo-binding domain lacking mechanochemical activity. This, in turn, likely competes with the native protein's function. These three approaches taken together indicate that the dynein heavy chain is an essential gene in Dictyostelium.
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Affiliation(s)
- M P Koonce
- Division of Molecular Medicine, Wadsworth Center, Albany, New York 12201-0509, USA.
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de Hostos EL, McCaffrey G, Sucgang R, Pierce DW, Vale RD. A developmentally regulated kinesin-related motor protein from Dictyostelium discoideum. Mol Biol Cell 1998; 9:2093-106. [PMID: 9693369 PMCID: PMC25463 DOI: 10.1091/mbc.9.8.2093] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The cellular slime mold Dictyostelium discoideum is an attractive system for studying the roles of microtubule-based motility in cell development and differentiation. In this work, we report the first molecular characterization of kinesin-related proteins (KRPs) in Dictyostelium. A PCR-based strategy was used to isolate DNA fragments encoding six KRPs, several of which are induced during the developmental program that is initiated by starvation. The complete sequence of one such developmentally regulated KRP (designated K7) was determined and found to be a novel member of the kinesin superfamily. The motor domain of K7 is most similar to that of conventional kinesin, but unlike conventional kinesin, K7 is not predicted to have an extensive alpha-helical coiled-coil domain. The nonmotor domain is unusual and is rich in Asn, Gln, and Thr residues; similar sequences are found in other developmentally regulated genes in Dictyostelium. K7, expressed in Escherichia coli, supports plus end-directed microtubule motility in vitro at a speed of 0.14 micron/s, indicating that it is a bona fide motor protein. The K7 motor is found only in developing cells and reaches a peak level of expression between 12 and 16 h after starvation. By immunofluorescence microscopy, K7 localizes to a membranous perinuclear structure. To examine K7 function, we prepared a null cell line but found that these cells show no gross developmental abnormalities. However, when cultivated in the presence of wild-type cells, the K7-null cells are mostly absent from the prestalk zone of the slug. This result suggests that in a population composed largely of wild-type cells, the absence of the K7 motor protein interferes either with the ability of the cells to localize to the prestalk zone or to differentiate into prestalk cells.
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Affiliation(s)
- E L de Hostos
- Department of Biochemistry and Cell Biology, Rice University, Houston Texas 77005, USA
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Koonce MP. Identification of a microtubule-binding domain in a cytoplasmic dynein heavy chain. J Biol Chem 1997; 272:19714-8. [PMID: 9242627 DOI: 10.1074/jbc.272.32.19714] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
As a molecular motor, dynein must coordinate ATP hydrolysis with conformational changes that lead to processive interactions with a microtubule and generate force. To understand how these processes occur, we have begun to map functional domains of a dynein heavy chain from Dictyostelium. The carboxyl-terminal 10-kilobase region of the heavy chain encodes a 380-kDa polypeptide that approximates the globular head domain. Attempts to further truncate this region fail to produce polypeptides that either bind microtubules or UV-vanadate cleave, indicating that the entire 10-kilobase fragment is necessary to produce a properly folded functional dynein head. We have further identified a region just downstream from the fourth P-loop that appears to constitute at least part of the microtubule-binding domain (amino acids 3182-3818). When deleted, the resulting head domain polypeptide no longer binds microtubules; when the excised region is expressed in vitro, it cosediments with added tubulin polymer. This microtubule-binding domain falls within an area of the molecule predicted to form extended alpha-helices. At least four discrete sites appear to coordinate activities required to bind the tubulin polymer, indicating that the interaction of dynein with microtubules is complex.
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Affiliation(s)
- M P Koonce
- Division of Molecular Medicine, Wadsworth Center, Empire State Plaza, Albany, New York 12201-0509, USA.
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Koonce MP. Chromosome walking in Dictyostelium: an application of the single specific primer PCR. METHODS IN MICROBIOLOGY 1997. [DOI: 10.1016/s0167-7012(97)00974-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Koonce MP, Samsó M. Overexpression of cytoplasmic dynein's globular head causes a collapse of the interphase microtubule network in Dictyostelium. Mol Biol Cell 1996; 7:935-48. [PMID: 8816999 PMCID: PMC275944 DOI: 10.1091/mbc.7.6.935] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cytoplasmic dynein is a minus-end directed microtubule-based motor. Using a molecular genetic approach, we have begun to dissect structure-function relationships of dynein in the cellular slime mold Dictyostelium. Expression of a carboxy-terminal 380-kDa fragment of the heavy chain produces a protein that approximates the size and shape of the globular, mechanochemical head of dynein. This polypeptide cosediments with microtubules in an ATP-sensitive fashion and undergoes a UV-vanadate cleavage reaction. The deleted amino-terminal region appears to participate in dimerization of the native protein and in binding the intermediate and light chains. Overexpression of the 380-kDa carboxy-terminal construct in Dictyostelium produces a distinct phenotype in which the interphase radial microtubule array appears collapsed. In many cells, the microtubules form loose bundles that are whorled around the nucleus. Similar expression of a central 107-kDa fragment of the heavy chain does not produce this result. The data presented here suggest that dynein may participate in maintaining the spatial pattern of the interphase microtubule network.
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Affiliation(s)
- M P Koonce
- Division of Molecular Medicine, Wadsworth Center, Albany, New York 12201-0509, USA
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