In vitro reconstitution of fish melanophore pigment aggregation

Nilsson, Helén; Walter, Steffen; Palazzo, Robert E.

doi:10.1002/1097-0169(200101)48:1<1::aid-cm1>3.0.co;2-d

Cited by 16 publications

(4 citation statements)

References 34 publications

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“…Microinjection of an antibody raised against dynein was shown to block pigment aggregation in fish melanophores (Nilsson & Wallin 1997). Addition of an antibody against dynein intermediate chain, previously shown to interfere with the binding of dynein to organelles (Steffen et al 1997), also blocked fish pigment aggregation in a cell-free system (Nilsson et al 2001). Dynein was shown to colocalize with pigment organelles in fish melanophores (Nilsson et al 1996) and mammalian melanocytes (Vancoillie et al 2000b).…”

Section: Microtubule-based Motorssupporting

confidence: 77%

Pigment Cells: A Model for the Study of Organelle Transport

Nascimento

Roland

Gelfand

2003

Annu. Rev. Cell Dev. Biol.

144

140

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Eukaryotic organisms rely on intracellular transport to position organelles and other components within their cells. Pigment cells provide an excellent model to study organelle transport as they specialize in the translocation of pigment granules in response to defined chemical signals. Pigment cells of lower vertebrates have traditionally been used as a model for these studies because these cells transport pigment organelles in a highly coordinated fashion, are easily cultured and transfected, are ideal for microsurgery, and are good for biochemical experiments, including in vitro analysis of organelle motility. Many important properties of organelle transport, for example, the requirement of two cytoskeletal filaments (actin and microtubules), the motor proteins involved, and the mechanisms of their regulation and interactions, have been studied using pigment cells of lower vertebrates. Genetic studies of mouse melanocytes allowed the discovery of essential elements involved in organelle transport including the myosin-Va motor and its receptor and adaptor molecules on the organelle surface. Future studies of pigment cells will contribute to our understanding of issues such as the cooperation among multiple motor proteins and the mechanisms of regulation of microtubule motors.

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Section: Microtubule-based Motorssupporting

confidence: 77%

Pigment Cells: A Model for the Study of Organelle Transport

Nascimento

Roland

Gelfand

2003

Annu. Rev. Cell Dev. Biol.

144

140

View full text Add to dashboard Cite

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“…The monoclonal antibodies we used (m74-1 and m74-2) are targeted against the interaction site between the dynein intermediate chain and the p150Glued subunit of dynactin, and were shown to inhibit cellular dynein activity in several studies (Krylyshkina et al, 2002;Nilsson et al, 2001;Steffen et al, 1997). We first confirmed their dynein inhibitory activity in COS-7 cells by measuring retrograde trafficking of transferrin (Fig.…”

Section: Bundle Transport Is Dependent On Cytoplasmic Dyneinmentioning

confidence: 93%

A microtubule-based, dynein-dependent force induces local cell protrusions: Implications for neurite initiation

et al. 2007

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A key event in neurite initiation is the accumulation of microtubule bundles at the neuron periphery. We hypothesized that such bundled microtubules may generate a force at the plasma membrane that facilitates neurite initiation. To test this idea we observed the behavior of microtubule bundles that were induced by the microtubule-associated protein MAP2c. Endogenous MAP2c contributes to neurite initiation in primary neurons, and exogeneous MAP2c is sufficient to induce neurites in Neuro-2a cells. We performed nocodazol washout experiments in primary neurons, Neuro-2a cells and COS-7 cells to investigate the underlying mechanism. During nocodazol washout, small microtubule bundles formed rapidly in the cytoplasm and immediately began to move toward the cell periphery in a unidirectional manner. In neurons and Neuro-2a cells, neurite-like processes extended within minutes and concurrently accumulated bundles of repolymerized microtubules. Speckle microscopy in COS-7 cells indicated that bundle movement was due to transport, not treadmilling. At the periphery bundles remained under a unidirectional force and induced local cell protrusions that were further enhanced by suppression of Rho kinase activity. Surprisingly, this bundle motility was independent of classical actin- or microtubule-based tracks. It was, however, reversed by function-blocking antibodies against dynein. Suppression of dynein expression in primary neurons by RNA interference severely inhibited the generation of new neurites, but not the elongation of existing neurites formed prior to dynein knockdown. Together, these cell biological data suggest that neuronal microtubule-associated proteins induce microtubule bundles that are pushed outward by dynein and locally override inward contraction to initiate neurite-like cell protrusions. A similar force-generating mechanism might participate in spontaneous initiation of neurites in developing neurons.

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“…A picture has begun to emerge showing tubulin based transport is essential for melanosome translocation in teleosts. It appears dynein moves melanosomes along microtubules during aggregation, while kinesin motors transport melanosome towards the periphery (Nilsson and Wallin, 1997;Nilsson et al, 2001;Rodionov et al, 1991;Rogers et al, 1997). The role of microfilaments in translocation is less well defined.…”

Section: Intracellular Control Of Colour Changementioning

confidence: 99%

Regulation of pigmentation in zebrafish melanophores

Logan¹,

Burn²,

Jackson³

2006

Pigment Cell Research

171

145

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In comparison with the molecular genetics of melanogenesis in mammals, the regulation of pigmentation in poikilothermic vertebrates is poorly understood. Mammals undergo morphological colour change under hormonal control, but strikingly, many lower vertebrates display a rapid physiological colour change in response to the same hormones. The recent provision of extensive genome sequencing data from teleost zebrafish, Danio rerio, provides the opportunity to define the genes and proteins mediating this physiological pigment response and characterise their function biologically. Here, we illustrate the background adaptation process in adults and larvae and describe a novel assay to visualize and directly quantify the rate of zebrafish melanophore pigment translocation in unprecedented detail. We demonstrate the resolution of this assay system; quantifying the zebrafish melanophore response to melanin-concentrating and melanocyte-stimulating hormones. Furthermore, we investigate the intracellular signalling downstream of hormone stimulation and the biomechanical processes involved in zebrafish pigment translocation, confirming the importance of cyclic adenosine monophosphate (cAMP) as a mediator of pigment translocation and finding intact microtubules are essential for both melanin dispersion and aggregation in zebrafish, but that microfilament disruption affects aggregation only. In conclusion, we propose these data establish the zebrafish as an experimental model for studying both physiological colour change and the molecular basis of pigment translocation.

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In vitro reconstitution of fish melanophore pigment aggregation

Cited by 16 publications

References 34 publications

Pigment Cells: A Model for the Study of Organelle Transport

Pigment Cells: A Model for the Study of Organelle Transport

A microtubule-based, dynein-dependent force induces local cell protrusions: Implications for neurite initiation

Regulation of pigmentation in zebrafish melanophores

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