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Dictyostelium dynamin B modulates cytoskeletal structures and membranous organelles.

Rai A, Nöthe H, Tzvetkov N, Korenbaum E, Manstein DJ - Cell. Mol. Life Sci. (2010)

Bottom Line: The mature form of dynamin B mediates a wide range and unique combination of functions.The modulating effect of dynamin B on the activity of the contractile vacuole system is unique for the Dictyostelium system.Other functions displayed by dynamin B are commonly associated with either classical dynamins or dynamin-related proteins.

View Article: PubMed Central - PubMed

Affiliation: Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Carl-Neuberg-Straße, Germany.

ABSTRACT
Dictyostelium discoideum cells produce five dynamin family proteins. Here, we show that dynamin B is the only member of this group of proteins that is initially produced as a preprotein and requires processing by mitochondrial proteases for formation of the mature protein. Our results show that dynamin B-depletion affects many aspects of cell motility, cell-cell and cell-surface adhesion, resistance to osmotic shock, and fatty acid metabolism. The mature form of dynamin B mediates a wide range and unique combination of functions. Dynamin B affects events at the plasma membrane, peroxisomes, the contractile vacuole system, components of the actin-based cytoskeleton, and cell adhesion sites. The modulating effect of dynamin B on the activity of the contractile vacuole system is unique for the Dictyostelium system. Other functions displayed by dynamin B are commonly associated with either classical dynamins or dynamin-related proteins.

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Cellular localization of dynamin B. a Electron micrograph showing colloidal gold immunostaining for dynamin B (black dots). YFP-tagged dynamin B is found in association with mitochondria (M), phagosomes (P), the contractile vacuole (CV), and the plasma membrane (PM). Arrows show gold particles. The inset shows an enlarged cross-section of a mitochondrion. Scale bars 0.2 μm. b Evanescent field fluorescence micrograph showing the presence of dynamin B-rich structures close to the plasma membrane. Scale bar 5 μm
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Fig3: Cellular localization of dynamin B. a Electron micrograph showing colloidal gold immunostaining for dynamin B (black dots). YFP-tagged dynamin B is found in association with mitochondria (M), phagosomes (P), the contractile vacuole (CV), and the plasma membrane (PM). Arrows show gold particles. The inset shows an enlarged cross-section of a mitochondrion. Scale bars 0.2 μm. b Evanescent field fluorescence micrograph showing the presence of dynamin B-rich structures close to the plasma membrane. Scale bar 5 μm

Mentions: The doughnut-like structures observed in fluorescence images of dynamin B-YFP-producing cells (Fig. 2a) suggest that dynamin B is predominantly associated with the outer mitochondrial membrane. To reveal the exact localization of dynamin B-YFP, we performed immunogold electron microscopy. Ultra-thin sections of dynamin B-YFP-producing cells were stained with a polyclonal anti-GFP antibody. The resulting electron micrographs show that dynamin B-YFP is in part associated with mitochondria (Fig. 3a). Additionally, the immunogold labeling indicated the presence of dynamin B on other membranous organelles and at the plasma membrane. Localization to the plasma membrane or structures in close association with it was confirmed by evanescent field microscopy (Fig. 3b).Fig. 3


Dictyostelium dynamin B modulates cytoskeletal structures and membranous organelles.

Rai A, Nöthe H, Tzvetkov N, Korenbaum E, Manstein DJ - Cell. Mol. Life Sci. (2010)

Cellular localization of dynamin B. a Electron micrograph showing colloidal gold immunostaining for dynamin B (black dots). YFP-tagged dynamin B is found in association with mitochondria (M), phagosomes (P), the contractile vacuole (CV), and the plasma membrane (PM). Arrows show gold particles. The inset shows an enlarged cross-section of a mitochondrion. Scale bars 0.2 μm. b Evanescent field fluorescence micrograph showing the presence of dynamin B-rich structures close to the plasma membrane. Scale bar 5 μm
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3142549&req=5

Fig3: Cellular localization of dynamin B. a Electron micrograph showing colloidal gold immunostaining for dynamin B (black dots). YFP-tagged dynamin B is found in association with mitochondria (M), phagosomes (P), the contractile vacuole (CV), and the plasma membrane (PM). Arrows show gold particles. The inset shows an enlarged cross-section of a mitochondrion. Scale bars 0.2 μm. b Evanescent field fluorescence micrograph showing the presence of dynamin B-rich structures close to the plasma membrane. Scale bar 5 μm
Mentions: The doughnut-like structures observed in fluorescence images of dynamin B-YFP-producing cells (Fig. 2a) suggest that dynamin B is predominantly associated with the outer mitochondrial membrane. To reveal the exact localization of dynamin B-YFP, we performed immunogold electron microscopy. Ultra-thin sections of dynamin B-YFP-producing cells were stained with a polyclonal anti-GFP antibody. The resulting electron micrographs show that dynamin B-YFP is in part associated with mitochondria (Fig. 3a). Additionally, the immunogold labeling indicated the presence of dynamin B on other membranous organelles and at the plasma membrane. Localization to the plasma membrane or structures in close association with it was confirmed by evanescent field microscopy (Fig. 3b).Fig. 3

Bottom Line: The mature form of dynamin B mediates a wide range and unique combination of functions.The modulating effect of dynamin B on the activity of the contractile vacuole system is unique for the Dictyostelium system.Other functions displayed by dynamin B are commonly associated with either classical dynamins or dynamin-related proteins.

View Article: PubMed Central - PubMed

Affiliation: Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Carl-Neuberg-Straße, Germany.

ABSTRACT
Dictyostelium discoideum cells produce five dynamin family proteins. Here, we show that dynamin B is the only member of this group of proteins that is initially produced as a preprotein and requires processing by mitochondrial proteases for formation of the mature protein. Our results show that dynamin B-depletion affects many aspects of cell motility, cell-cell and cell-surface adhesion, resistance to osmotic shock, and fatty acid metabolism. The mature form of dynamin B mediates a wide range and unique combination of functions. Dynamin B affects events at the plasma membrane, peroxisomes, the contractile vacuole system, components of the actin-based cytoskeleton, and cell adhesion sites. The modulating effect of dynamin B on the activity of the contractile vacuole system is unique for the Dictyostelium system. Other functions displayed by dynamin B are commonly associated with either classical dynamins or dynamin-related proteins.

Show MeSH
Related in: MedlinePlus