Structural interaction of cytoskeletal components

Schliwa, Manfred; Blerkom, Jonathan Van

doi:10.1083/jcb.90.1.222

Cited by 738 publications

(357 citation statements)

References 43 publications

(31 reference statements)

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“…The current study shows that the formation of ovarian cysts in sows is associated to alterations in the expression of some cytoskeletal proteins. These molecules act in the formation of cell contacts and in the determination of the cell morphology (Schliwa & Van Blerkom 1981, Luna & Hitt 1992. Changes in the intermediate filaments have also been observed in ovine normal ovaries, affecting the organization of the cytoskeleton of corpus luteum and atresic follicles (Marettova & Maretta 2002).…”

Section: Discussionmentioning

confidence: 91%

Cytoskeletal proteins in the follicular wall of normal andcystic ovaries of sows

et al. 2015

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The expression of cytoskeletal proteins was evaluated immunohistochemically in 36 normal ovaries sampled from 18 sows and 44 cystic ovaries sampled from of 22 sows, was evaluated. All sows had history of reproductive problems, such as infertility or subfertility. The immunohistochemically stained area (IHCSA) was quantified through image analysis to evaluate the expression of these proteins in the follicular wall of secondary, tertiary, and cystic follicles. Cytokeratins (CK) immunoreactivity was strong in the granulosa cell layer (GC) and mild in the theca interna (TI) and externa (TE) of the normal follicles. There was severe reduction of the reaction to CK in the GC in the cystic follicles, mainly in the luteinized cysts. The immunoreactivity for vimentin was higher in the GC from normal and cystic follicles in contrast with the other follicular structures. In the luteinized cysts, the IHCSA for vimentin was significantly higher in TI and in both observed cysts, the labeling was more accentuated in TE. Immunohistochemical detection of desmin and α-SMA was restricted to the TE, without differences between the normal and cystic follicles. The results of the current study show that the development of ovarian cysts in sows is associated to changes in the expression of the cytoskeletal proteins CK and vimentin.

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Section: Discussionmentioning

confidence: 91%

Cytoskeletal proteins in the follicular wall of normal andcystic ovaries of sows

et al. 2015

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“…Nrk17p-GFP was not retained in cells using the standard fixation procedure. Therefore, Nrk17p-GFP cells were fixed with 15 l of 2% paraformaldehyde in PHEM buffer (Schliwa and van Blerkom, 1981) and after 10 -15 s permeabilized with 10 l of 0.5% Triton X-100 in the same buffer. We could not retain Nrk30p-GFP inside cells under fixation conditions, which included detergent permeabilization.…”

Section: Immunofluorescencementioning

confidence: 99%

Members of the NIMA-related Kinase Family Promote Disassembly of Cilia by Multiple Mechanisms

Włoga

Camba

Rogowski

et al. 2006

MBoC

105

103

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The genome of Tetrahymena thermophila contains 39 loci encoding NIMA-related kinases (NRKs), an extraordinarily large number for a unicellular organism. Evolutionary analyses grouped these sequences into several subfamilies, some of which have orthologues in animals, whereas others are protist specific. When overproduced, NRKs of three subfamilies caused rapid shortening of cilia. Ultrastructural studies revealed that each NRK triggered ciliary resorption by a distinct mechanism that involved preferential depolymerization of a subset of axonemal microtubules, at either the distal or proximal end. Overexpression of a kinase-inactive variant caused lengthening of cilia, indicating that constitutive NRK-mediated resorption regulates the length of cilia. Each NRK preferentially resorbed a distinct subset of cilia, depending on the location along the anteroposterior axis. We also show that normal Tetrahymena cells maintain unequal length cilia. We propose that ciliates used a large number of NRK paralogues to differentially regulate the length of specific subsets of cilia in the same cell. INTRODUCTIONHow the size of organelles is determined is an important and largely unanswered question. Cilia have emerged as a model organelle to study the mechanism of size regulation (Marshall, 2002). The size of an organelle is determined by the balance between assembly pathways that deliver structural components and disassembly pathways that remove components. In cilia, the intraflagellar transport (IFT), a bidirectional motility system that operates inside cilia (Rosenbaum and Witman, 2002;Scholey, 2003), plays a key role in length regulation. The anterograde IFT supplies structural subunits during assembly (Piperno et al., 1996;Qin et al., 2005) and maintains the axoneme after assembly (Brown et al., 1999). The retrograde IFT recycles the IFT machinery (Signor et al., 1999) and removes ciliary structural components that turn over (Qin et al., 2004). This turnover is the basis of the disassembly pathway (Stephens, 1997;Marshall and Rosenbaum, 2001;Song and Dentler, 2001;Thazhath et al., 2004). Experimental data and mathematical modeling in Chlamydomonas reinhardtii indicate that the length of flagella is dependent on the rates of elongation (equivalent to the efficiency of anterograde IFT) and disassembly. As the flagellum grows, the rate of elongation decreases due to the limited supply of IFT components that need to travel longer distances to the tip (Marshall and Rosenbaum, 2001). According to the "balance point model," the steady-state length is achieved when the rate of elongation equals the rate of disassembly (Marshall and Rosenbaum, 2001;Marshall et al., 2005).The length of already assembled cilia can be reduced drastically using two mechanisms: autotomy or resorption (reviewed by Quarmby, 2004). During autotomy, the axoneme breaks off from the basal body, the cilium falls off, and the plasma membrane reseals over the basal body. Protists undergo autotomy in response to low pH (Lewin et al., 1982). It is unclear whether...

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“…After a brief rinse in phosphate buffer, they were fixed for 15 min with 0.5% glutaraldehyde in modified PHEM buffer (12 mM PIPES, 5 mM HEPES, 1,6 mM EGTA, 1 mM MgCl 2 , pH 7; Schliwa and van Blerkom, 1981) supplemented with 0.5% Triton X-100. Suitable cells containing one or more free centrosomes, as judged by GFP and 4,6-diamidino-2-phenylindole (DAPI) fluorescence, were selected and photographed.…”

Section: Electron Microscopymentioning

confidence: 99%

Regulated Expression of the Centrosomal Protein DdCP224 Affects Microtubule Dynamics and Reveals Mechanisms for the Control of Supernumerary Centrosome Number

Gräf

Euteneuer

et al. 2003

MBoC

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The Dictyostelium XMAP215 family member DdCP224 is involved in centrosome duplication and cytokinesis and is concentrated at the centrosome and microtubule tips. Herein, we have created a DdCP224 promoter replacement mutant that allows both over-and underexpression. Overexpression led to supernumerary microtubule-organizing centers and, independently, an increase of the number of multinuclear cells. Electron microscopy demonstrated that supernumerary microtubule-organizing centers represented bona fide centrosomes. Live cell imaging of DdCP224-green fluorescent protein mutants also expressing green fluorescent protein-histone2B as a DNA label revealed that supernumerary centrosomes were also competent of cell cycle-dependent duplication. In contrast, underexpression of DdCP224 inhibited cell growth, reduced the number and length of astral microtubules, and caused nocodazole hypersensitivity. Moreover, microtubule regrowth after nocodazole removal was dependent on DdCP224. Underexpression also resulted in a striking disappearance of supernumerary centrosomes and multinuclear cells caused by previous overexpression. We show for the first time by live cell observation that the number of supernumerary centrosomes can be reduced either by centrosome fusion (coalescence) or by the formation of cytoplasts containing supernumerary centrosomes during cytokinesis. INTRODUCTIONIn dividing cells, control of centrosome number is essential for the fidelity of mitosis and maintenance of euploidy. Supernumerary centrosomes are a hallmark of tumor cells, although it is still a matter of discussion whether their appearance is a cause or a consequence of carcinogenesis (Lingle et al., 2002;Nigg, 2002). However, it is widely accepted that supernumerary centrosomes contribute to the formation of multipolar spindles and thus to defective chromosome segregation. Although most of the daughter cells resulting from such mitotic chaos will die, some of them will acquire the potential for neoplastic growth in spite of supernumerary centrosomes and aneuploidy, as they regain the ability to form a bipolar spindle. Brinkley (2001) suggested two mechanisms how this can be achieved: first, "deamplification" of supernumerary centrosomes by elimination or inactivation, and second, fusion or "coalescence" of supernumerary centrosomes resulting in one or two compound microtubule-organizing centers (MTOCs).Herein, we have studied the fate of supernumerary centrosomes in a simple model system. In Dictyostelium amoebae, one molecular component involved in the formation of supernumerary centrosomes is DdCP224, a member of the XMAP215 family of microtubule-associated proteins (Gräf et al., 2000). In most species, these proteins are long, thin, monomeric molecules with a size of ϳ 230 kDa (Cassimeris et al., 2001). Their ubiquitous occurrence, even in plants, suggests indispensible functions (Ohkura et al., 2001). XMAP215, for instance, is a promoter of microtubule elongation due to a suppression of catastrophe events induced by the Kin I family kinesin ...

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Structural interaction of cytoskeletal components

Cited by 738 publications

References 43 publications

Cytoskeletal proteins in the follicular wall of normal andcystic ovaries of sows

Cytoskeletal proteins in the follicular wall of normal andcystic ovaries of sows

Members of the NIMA-related Kinase Family Promote Disassembly of Cilia by Multiple Mechanisms

Regulated Expression of the Centrosomal Protein DdCP224 Affects Microtubule Dynamics and Reveals Mechanisms for the Control of Supernumerary Centrosome Number

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