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William J Sullivan - One of the best experts on this subject based on the ideXlab platform.
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actin cytoskeleton remodeling during early drosophila furrow formation requires recycling endosomal components Nuclear Fallout and rab11
Journal of Cell Biology, 2003Co-Authors: Blake Riggs, Gilles R X Hickson, Johanne Matheson, Gwyn W Gould, Wendy F Rothwell, Sarah Mische, Thomas S Hays, William J SullivanAbstract:Cytokinesis requires a dramatic remodeling of the cortical cytoskeleton as well as membrane addition. The Drosophila pericentrosomal protein, Nuclear-Fallout (Nuf), provides a link between these two processes. In nuf-derived embryos, actin remodeling and membrane recruitment during the initial stages of metaphase and cellular furrow formation are disrupted. Nuf is a homologue of arfophilin-2, an ADP ribosylation factor effector that binds Rab11 and influences recycling endosome (RE) organization. Here, we show that Nuf is an important component of the RE, and that these phenotypes are a consequence of Nuf activities at the RE. Nuf exhibits extensive colocalization with Rab11, a key RE component. GST pull-downs and the presence of a conserved Rab11-binding domain in Nuf demonstrate that Nuf and Rab11 physically associate. In addition, Nuf and Rab11 are mutually required for their localization to the RE. Embryos with reduced levels of Rab11 produce membrane recruitment and actin remodeling defects strikingly similar to nuf-derived embryos. These analyses support a common role for Nuf and Rab11 at the RE in membrane trafficking and actin remodeling during the initial stages of furrow formation.
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arfophilins are dual arf rab 11 binding proteins that regulate recycling endosome distribution and are related to drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
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Arfophilins Are Dual Arf/Rab 11 Binding Proteins That Regulate Recycling Endosome Distribution and Are Related to Drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
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Discontinuous Actin Hexagon, a Protein Essential for Cortical Furrow Formation in Drosophila, Is Membrane Associated and Hyperphosphorylated
Molecular Biology of the Cell, 2000Co-Authors: Claire X. Zhang, William J Sullivan, Wendy F Rothwell, Tao-shih HsiehAbstract:discontinuous actin hexagon (dah) is a maternal-effect gene essential for the formation of cortical furrows during Drosophila embryogenesis, and DAH protein colocalizes with actin in these furrows. Biochemical fractionation experiments presented here demonstrate that DAH is highly enriched in the membrane fraction and that its membrane association is resistant to high-salt and alkaline washes. Furthermore, it partitions into the detergent phase of the Triton X-114 solution, indicating its tight binding to the membranes. DAH can also interact with the actin cytoskeleton, because a fraction of DAH remains insoluble to nonionic detergent along with actin. These biochemical characterizations suggest that DAH may play a role in the linkage of the actin cytoskeleton to membranes. Using phosphatase inhibitors, we detected multiple phosphorylated forms of DAH in embryonic extracts. The DAH phosphorylation peaks during cellularization, a stage at which DAH function is critical. A kinase activity is coimmunoprecipitated with the DAH complex and hyperphosphorylates DAH in vitro. Purified casein kinase I can also hyperphosphorylate DAH in the immune complex. Both DAH localization and phosphorylation are disrupted in another maternal-effect mutant, Nuclear-Fallout. It is possible that Nuclear-Fallout collaborates with dah and directs DAH protein localization to the cortical furrows.
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Nuclear Fallout a drosophila protein that cycles from the cytoplasm to the centrosomes regulates cortical microfilament organization
Development, 1998Co-Authors: Wendy F Rothwell, Patrick Fogarty, Christine M Field, William J SullivanAbstract:Nuclear Fallout (nuf) is a maternal effect mutation that specifically disrupts the cortical syncytial divisions during Drosophila embryogenesis. We show that the nuf gene encodes a highly phosphorylated novel protein of 502 amino acids with C-terminal regions predicted to form coiled-coils. During prophase of the late syncytial divisions, Nuf concentrates at the centrosomes and is generally cytoplasmic throughout the rest of the Nuclear cycle. In nuf-derived embryos, the recruitment of actin from caps to furrows during prophase is disrupted. This results in incomplete metaphase furrows specifically in regions distant from the centrosomes. The nuf mutation does not disrupt anillin or peanut recruitment to the metaphase furrows indicating that Nuf is not involved in the signaling of metaphase furrow formation. These results also suggest that anillin and peanut localization are independent of actin localization to the metaphase furrows. nuf also disrupts the initial stages of cellularization and produces disruptions in cellularization furrows similar to those observed in the metaphase furrows. The localization of Nuf to centrosomal regions throughout cellularization suggests that it plays a similar role in the initial formation of both metaphase and cellularization furrows. A model is presented in which Nuf provides a functional link between centrosomes and microfilaments.
Gwyn W Gould - One of the best experts on this subject based on the ideXlab platform.
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actin cytoskeleton remodeling during early drosophila furrow formation requires recycling endosomal components Nuclear Fallout and rab11
Journal of Cell Biology, 2003Co-Authors: Blake Riggs, Gilles R X Hickson, Johanne Matheson, Gwyn W Gould, Wendy F Rothwell, Sarah Mische, Thomas S Hays, William J SullivanAbstract:Cytokinesis requires a dramatic remodeling of the cortical cytoskeleton as well as membrane addition. The Drosophila pericentrosomal protein, Nuclear-Fallout (Nuf), provides a link between these two processes. In nuf-derived embryos, actin remodeling and membrane recruitment during the initial stages of metaphase and cellular furrow formation are disrupted. Nuf is a homologue of arfophilin-2, an ADP ribosylation factor effector that binds Rab11 and influences recycling endosome (RE) organization. Here, we show that Nuf is an important component of the RE, and that these phenotypes are a consequence of Nuf activities at the RE. Nuf exhibits extensive colocalization with Rab11, a key RE component. GST pull-downs and the presence of a conserved Rab11-binding domain in Nuf demonstrate that Nuf and Rab11 physically associate. In addition, Nuf and Rab11 are mutually required for their localization to the RE. Embryos with reduced levels of Rab11 produce membrane recruitment and actin remodeling defects strikingly similar to nuf-derived embryos. These analyses support a common role for Nuf and Rab11 at the RE in membrane trafficking and actin remodeling during the initial stages of furrow formation.
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arfophilins are dual arf rab 11 binding proteins that regulate recycling endosome distribution and are related to drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
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Arfophilins Are Dual Arf/Rab 11 Binding Proteins That Regulate Recycling Endosome Distribution and Are Related to Drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
Gilles R X Hickson - One of the best experts on this subject based on the ideXlab platform.
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actin cytoskeleton remodeling during early drosophila furrow formation requires recycling endosomal components Nuclear Fallout and rab11
Journal of Cell Biology, 2003Co-Authors: Blake Riggs, Gilles R X Hickson, Johanne Matheson, Gwyn W Gould, Wendy F Rothwell, Sarah Mische, Thomas S Hays, William J SullivanAbstract:Cytokinesis requires a dramatic remodeling of the cortical cytoskeleton as well as membrane addition. The Drosophila pericentrosomal protein, Nuclear-Fallout (Nuf), provides a link between these two processes. In nuf-derived embryos, actin remodeling and membrane recruitment during the initial stages of metaphase and cellular furrow formation are disrupted. Nuf is a homologue of arfophilin-2, an ADP ribosylation factor effector that binds Rab11 and influences recycling endosome (RE) organization. Here, we show that Nuf is an important component of the RE, and that these phenotypes are a consequence of Nuf activities at the RE. Nuf exhibits extensive colocalization with Rab11, a key RE component. GST pull-downs and the presence of a conserved Rab11-binding domain in Nuf demonstrate that Nuf and Rab11 physically associate. In addition, Nuf and Rab11 are mutually required for their localization to the RE. Embryos with reduced levels of Rab11 produce membrane recruitment and actin remodeling defects strikingly similar to nuf-derived embryos. These analyses support a common role for Nuf and Rab11 at the RE in membrane trafficking and actin remodeling during the initial stages of furrow formation.
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arfophilins are dual arf rab 11 binding proteins that regulate recycling endosome distribution and are related to drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
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Arfophilins Are Dual Arf/Rab 11 Binding Proteins That Regulate Recycling Endosome Distribution and Are Related to Drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
K Muck - One of the best experts on this subject based on the ideXlab platform.
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The Long-term Decrease of 90Sr in the Environment and its Transfer to Man after a Nuclear Fallout
Radiation Protection Dosimetry, 2001Co-Authors: K Muck, M. Sinojmeri, H. Whilidal, F. StegerAbstract:Due to its long physical half-life, and the fact that its long-term mobility in the environment as well as its radiotoxicity is higher than that of 137 Cs, the long-term bio-availability of 90 Sr in the environment is of importance with regard to the long-term population exposure after Fallout from Nuclear weapons detonations or a severe reactor accident. It will also substantially influence the time-span required until re-utilisation of highly contaminated territory is possible again. An assessment of the longterm decrease of the activity concentration in all foodstuffs relevant for internal exposure after severe 90 Sr Fallout was performed. The observed effective half-lives were approximately 1.8-2. 1 years in the first 2-3 years after the end of Fallout and 8-10 years in the following three decades. This is equivalent to a hiological half-life of about 13,2 years and results in a total 50 year dose of 6.2 times the first year exposure. Due to this decline in 90 Sr-availability, the average annual activity intake of 90 Sr in Austria has decreased from 840 Bq at the climax of the Nuclear weapons tests to about 42 Bq in 1997 for adults, and from 500 Bq to about 35 Bq for 1 year old infants. This is equivalent to a 90 Sr ingestion dose of 1.2 μSv for adults and 2.5 μSv for 1 year old infants in 1997 or less than 0.4% of the ingestion dose by natural radionuclides in the diet.
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long term effective decrease of cesium concentration in foodstuffs after Nuclear Fallout
Health Physics, 1997Co-Authors: K MuckAbstract:AbstractThe long-term decrease in activity concentrations in various foodstuffs relevant for the long-term ingestion dose after a Nuclear Fallout is reviewed. The effective decrease observed in various countries of Central Europe after the Chernobyl accident are compared to the effective decrease ob
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longterm reduction of caesium concentration in milk after Nuclear Fallout
Science of The Total Environment, 1995Co-Authors: K MuckAbstract:Abstract Time trends in activity concentrations in milk as observed in Austria after the Chernobyl accident are presented. Both the short term decrease immediately after Fallout and the medium term decline in the years following the event are very important for estimating the total exposure to be expected from a given deposition. In order to avoid artifacts due to local Fallout, plant variations, or differences in the metabolism of single animals, large areas of production were used for the observations. This was achieved by observations of activity concentrations in milk powder, produced in large milk powder plants in Austria. After an initial decay with an approximate half-life of 34 days for the period of May to August 1986, a slower decrease in activity was observed during the following years. Observed half-lives are in the range of 1.5–2.0 a. Differences in the decrease observed between the different producing areas are discussed. The radiocesium contamination of milk and milk products depends directly on its presence in grass or hay and therefore, time trends observed in milk correspond closely to the time trend in these fodders. Other foodstuffs which are also produced on grass and hay, such as beef or lamb, should therefore display similar decay patterns, except for the early period after Fallout when the biological half-lives in the animals influences the decrease.
Blake Riggs - One of the best experts on this subject based on the ideXlab platform.
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actin cytoskeleton remodeling during early drosophila furrow formation requires recycling endosomal components Nuclear Fallout and rab11
Journal of Cell Biology, 2003Co-Authors: Blake Riggs, Gilles R X Hickson, Johanne Matheson, Gwyn W Gould, Wendy F Rothwell, Sarah Mische, Thomas S Hays, William J SullivanAbstract:Cytokinesis requires a dramatic remodeling of the cortical cytoskeleton as well as membrane addition. The Drosophila pericentrosomal protein, Nuclear-Fallout (Nuf), provides a link between these two processes. In nuf-derived embryos, actin remodeling and membrane recruitment during the initial stages of metaphase and cellular furrow formation are disrupted. Nuf is a homologue of arfophilin-2, an ADP ribosylation factor effector that binds Rab11 and influences recycling endosome (RE) organization. Here, we show that Nuf is an important component of the RE, and that these phenotypes are a consequence of Nuf activities at the RE. Nuf exhibits extensive colocalization with Rab11, a key RE component. GST pull-downs and the presence of a conserved Rab11-binding domain in Nuf demonstrate that Nuf and Rab11 physically associate. In addition, Nuf and Rab11 are mutually required for their localization to the RE. Embryos with reduced levels of Rab11 produce membrane recruitment and actin remodeling defects strikingly similar to nuf-derived embryos. These analyses support a common role for Nuf and Rab11 at the RE in membrane trafficking and actin remodeling during the initial stages of furrow formation.
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arfophilins are dual arf rab 11 binding proteins that regulate recycling endosome distribution and are related to drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
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Arfophilins Are Dual Arf/Rab 11 Binding Proteins That Regulate Recycling Endosome Distribution and Are Related to Drosophila Nuclear Fallout
Molecular Biology of the Cell, 2003Co-Authors: Gilles R X Hickson, Johanne Matheson, Blake Riggs, Valerie H Maier, Andrew B Fielding, Rytis Prekeris, William J Sullivan, Francis A Barr, Gwyn W GouldAbstract:Arfophilin is an ADP ribosylation factor (Arf) binding protein of unknown function. It is identical to the Rab11 binding protein eferin/Rab11-FIP3, and we show it binds both Arf5 and Rab11. We describe a related protein, arfophilin-2, that interacts with Arf5 in a nucleotide-dependent manner, but not Arf1, 4, or 6 and also binds Rab11. Arfophilin-2 localized to a periNuclear compartment, the centrosomal area, and focal adhesions. The localization of arfophilin-2 to the periNuclear compartment was selectively blocked by overexpression of Arf5-T31N. In contrast, a green fluorescent protein-arfophilin-2 chimera or arfophilin-2 deletions were localized around the centrosome in a region that was also enriched for transferrin receptors and Rab11 but not early endosome markers, suggesting that the distribution of the endosomal recycling compartment was altered. The arfophilins belong to a conserved family that includes Drosophila melanogaster Nuclear Fallout, a centrosomal protein required for cellularization. Expression of green fluorescent protein-Nuclear Fallout in HeLa cells resulted in a similar phenotype, indicative of functional homology and thus implicating the arfophilins in mitosis/cytokinesis. We suggest that the novel dual GTPase-binding capacity of the arfophilins could serve as an interface of signals from Rab and Arf GTPases to regulate membrane traffic and integrate distinct signals in the late endosomal recycling compartment.
