Cytoplasmic dynein intermediate chain and heavy chain are dependent upon each other for microtubule end localization in Aspergillus nidulans

2002 ◽  
Vol 44 (2) ◽  
pp. 381-392 ◽  
Author(s):  
Jun Zhang ◽  
Gongshe Han ◽  
Xin Xiang
1999 ◽  
Vol 147 (6) ◽  
pp. 1261-1274 ◽  
Author(s):  
Shuo Ma ◽  
Leda Triviños-Lagos ◽  
Ralph Gräf ◽  
Rex L. Chisholm

Cytoplasmic dynein intermediate chain (IC) mediates dynein–dynactin interaction in vitro (Karki, S., and E.L. Holzbaur. 1995. J. Biol. Chem. 270:28806–28811; Vaughan, K.T., and R.B. Vallee. 1995. J. Cell Biol. 131:1507–1516). To investigate the physiological role of IC and dynein–dynactin interaction, we expressed IC truncations in wild-type Dictyostelium cells. ICΔC associated with dynactin but not with dynein heavy chain, whereas ICΔN truncations bound to dynein but bound dynactin poorly. Both mutations resulted in abnormal localization to the Golgi complex, confirming dynein function was disrupted. Striking disorganization of interphase microtubule (MT) networks was observed when mutant expression was induced. In a majority of cells, the MT networks collapsed into large bundles. We also observed cells with multiple cytoplasmic asters and MTs lacking an organizing center. These cells accumulated abnormal DNA content, suggesting a defect in mitosis. Striking defects in centrosome morphology were also observed in IC mutants, mostly larger than normal centrosomes. Ultrastructural analysis of centrosomes in IC mutants showed interphase accumulation of large centrosomes typical of prophase as well as unusually paired centrosomes, suggesting defects in centrosome replication and separation. These results suggest that dynactin-mediated cytoplasmic dynein function is required for the proper organization of interphase MT network as well as centrosome replication and separation in Dictyostelium.


2001 ◽  
Vol 276 (17) ◽  
pp. 14067-14074 ◽  
Author(s):  
Yu-Keung Mok ◽  
Kevin W.-H. Lo ◽  
Mingjie Zhang

2002 ◽  
Vol 13 (5) ◽  
pp. 1722-1734 ◽  
Author(s):  
Sher Karki ◽  
Lee A. Ligon ◽  
Jamison DeSantis ◽  
Mariko Tokito ◽  
Erika L. F. Holzbaur

We screened for polypeptides that interact specifically with dynein and identified a novel 24-kDa protein (PLAC-24) that binds directly to dynein intermediate chain (DIC). PLAC-24 is not a dynactin subunit, and the binding of PLAC-24 to the dynein intermediate chain is independent of the association between dynein and dynactin. Immunocytochemistry using PLAC-24–specific polyclonal antibodies revealed a punctate perinuclear distribution of the polypeptide in fibroblasts and isolated epithelial cells. However, as epithelial cells in culture make contact with adjacent cells, PLAC-24 is specifically recruited to the cortex at sites of contact, where the protein colocalizes with components of the adherens junction. Disruption of the cellular cytoskeleton with latrunculin or nocodazole indicates that the localization of PLAC-24 to the cortex is dependent on intact actin filaments but not on microtubules. Overexpression of β-catenin also leads to a loss of PLAC-24 from sites of cell-cell contact. On the basis of these data and the recent observation that cytoplasmic dynein is also localized to sites of cell-cell contact in epithelial cells, we propose that PLAC-24 is part of a multiprotein complex localized to sites of intercellular contact that may function to tether microtubule plus ends to the actin-rich cellular cortex.


2015 ◽  
Vol 208 (6) ◽  
pp. 683-692 ◽  
Author(s):  
Wenjing Li ◽  
Peishan Yi ◽  
Guangshuo Ou

Cilium formation and maintenance require intraflagellar transport (IFT). Although much is known about kinesin-2–driven anterograde IFT, the composition and regulation of retrograde IFT-specific dynein remain elusive. Components of cytoplasmic dynein may participate in IFT; however, their essential roles in cell division preclude functional studies in postmitotic cilia. Here, we report that inducible expression of the clustered regularly interspaced short palindromic repeats (CRISPR)–Cas9 system in Caenorhabditis elegans generated conditional mutations in IFT motors and particles, recapitulating ciliary defects in their null mutants. Using this method to bypass the embryonic requirement, we show the following: the dynein intermediate chain, light chain LC8, and lissencephaly-1 regulate retrograde IFT; the dynein light intermediate chain functions in dendrites and indirectly contributes to ciliogenesis; and the Tctex and Roadblock light chains are dispensable for cilium assembly. Furthermore, we demonstrate that these components undergo biphasic IFT with distinct transport frequencies and turnaround behaviors. Together, our results suggest that IFT–dynein and cytoplasmic dynein have unique compositions but also share components and regulatory mechanisms.


1999 ◽  
Vol 9 (8) ◽  
pp. 425-428 ◽  
Author(s):  
Lisbeth Berrueta ◽  
Jennifer S. Tirnauer ◽  
Scott C. Schuyler ◽  
David Pellman ◽  
Barbara E. Bierer

Genetics ◽  
1995 ◽  
Vol 139 (3) ◽  
pp. 1223-1232 ◽  
Author(s):  
G H Goldman ◽  
N R Morris

Abstract Cytoplasmic dynein is a large molecular weight protein complex that functions as a microtubule-dependent, negative, end-directed "motor." Mutations in nudA, which encodes the heavy chain of cytoplasmic dynein, inhibit nuclear migration in Aspergillus nidulans. This paper describes the selection and characterization of extragenic suppressors of the nudA1 mutation preparatory to the identification of other proteins that interact directly or indirectly with the cytoplasmic dynein heavy chain. To facilitate future cloning of the suppressor genes, we have searched particularly for extragenic suppressor mutations that also convey a selectable phenotype, such as cold or dimethyl sulfoxide sensitivity. Genetic analysis of 16 revertants has defined at least five extragenic suppressors of nudA1 (snaA-E). All the sna mutations except one were recessive in diploids homozygous for nudA1 and heterozygous for sna mutations. To characterize the nuclear migration phenotype in the sna mutants, conidia of one representative of each complementation group were germinated, fixed and nuclei stained. The sna mutants display partial suppression of the nudA1 nuclear migration defect. Although conidiophores were produced in the sna mutants, they failed to develop normally and to produce spores. Examination of the nudA1,sna conidiophores under the microscope showed that nuclear migration into the metulae and phialides was defective.


Genetics ◽  
2002 ◽  
Vol 162 (3) ◽  
pp. 1211-1220 ◽  
Author(s):  
Kristin L M Boylan ◽  
Thomas S Hays

Abstract The microtubule motor cytoplasmic dynein powers a variety of intracellular transport events that are essential for cellular and developmental processes. A current hypothesis is that the accessory subunits of the dynein complex are important for the specialization of cytoplasmic dynein function. In a genetic approach to understanding the range of dynein functions and the contribution of the different subunits to dynein motor function and regulation, we have identified mutations in the gene for the cytoplasmic dynein intermediate chain, Dic19C. We used a functional Dic transgene in a genetic screen to recover X-linked lethal mutations that require this transgene for viability. Three Dic mutations were identified and characterized. All three Dic alleles result in larval lethality, demonstrating that the intermediate chain serves an essential function in Drosophila. Like a deficiency that removes Dic19C, the Dic mutations dominantly enhance the rough eye phenotype of Glued1, a dominant mutation in the gene for the p150 subunit of the dynactin complex, a dynein activator. Additionally, we used complementation analysis to identify an existing mutation, shortwing (sw), as an allele of the dynein intermediate chain gene. Unlike the Dic alleles isolated de novo, shortwing is homozygous viable and exhibits recessive and temperature-sensitive defects in eye and wing development. These phenotypes are rescued by the wild-type Dic transgene, indicating that shortwing is a viable allele of the dynein intermediate chain gene and revealing a novel role for dynein function during wing development.


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