The Experts below are selected from a list of 1260 Experts worldwide ranked by ideXlab platform
Kenichi Yoshida - One of the best experts on this subject based on the ideXlab platform.
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K (2001) Nitric oxide promotes germ cell necrosis in the delayed phase after experimental testicular torsion of rat. Biol Reprod 65:514–521
2016Co-Authors: Koji Shiraishi, Katsusuke Naito, Kenichi YoshidaAbstract:The purpose of this study is to determine whether inducible nitric oxide synthase (iNOS) is involved in the pathogenesis of testicular ischemia-reperfusion (I/R) injury in association with germ cell death, through either necrosis or apoptosis. Western blot analysis showed that iNOS expression was markedly in-creased 1 h after ischemia, and was accompanied by a huge nitric oxide (NO) production, as measured by the Griess meth-od, with a peak at 48 h of reperfusion. Immunohistochemistry showed that iNOS was expressed predominantly in the macro-phage-like cells infiltrated in the interstitial tissues of the testis. Intraperitoneal injection of aminoguanidine (AMG) (400 mg/day), the inhibitor of iNOS, reduced NO production by 57.7 % at 96 h of reperfusion. Calpain activation and proteolysis of a-Fodrin induced by I/R were inhibited by AMG. Germ cell apoptosis was demonstrated by in situ TUNEL and DNA frag-mentation on agarose gel electrophoresis. Germ cell apoptosis was maximally induced at 24 h of reperfusion, and was not in-hibited by AMG. NO produced by iNOS in the delayed phase of reperfusion promoted a-Fodrin proteolysis, which is closely associated with necrosis. Inducible NOS inhibition combined with calpain inhibition may improve impaired spermatogenesis after testicular torsion. apoptosis, nitric oxide, testi
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activation of endothelial nitric oxide synthase in contralateral testis during unilateral testicular torsion in rats
Archives of Andrology, 2003Co-Authors: Koji Shiraishi, Kenichi Yoshida, Katsusuke NaitoAbstract:There are controversies about the injury of the contralateral testis during unilateral testicular torsion (UTT). An autonomic reflex arc between bilateral testes has been proposed. The authors focused on the involvement of nitric oxide (NO) in the contralateral testis during UTT. Eight-week-old male Wistar rats underwent unilateral torsion (1 h)-detorsion (up to 24 h). NO synthase (NOS) activity was detected as NADPH-diaphorase activity after fixation by paraformaldehyde. N-nitro-L-Arginine methyl ester (L-NAME, 20 mg/kg) was injected intravenously to the other group of rats. To evaluate the testicular injury, proteolysis of alpha-Fodrin production was detected by Western blotting. Apoptosis of the germ cells was evaluated by TUNEL. Long-term effect on spermatogenesis was evaluated by flow cytometry at 60 days after UTT. Transient activation of NOS was detected following the proteolysis of alpha-Fodrin in the contralateral testis. L-NAME inhibited these alterations. NADPH-diaphorase activity and eNOS immunoreactivity were co-localized in the endothelial cells. These reactions were not observed in other organs. There was neither enhanced apoptosis nor deteriorated spermatogenesis in the contralateral testis during and 60 days after UTT. In the contralateral testis, eNOS-derived NO regulates the vasomotor function against unilateral testicular torsion, whereas it acts slightly cytotoxic. These results suggest the possible involvement of a testis-specific neurovasomotor reflex between the bilateral testes.
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postischemic reperfusion induces α Fodrin proteolysis by m calpain in the synaptosome and nucleus in rat brain
Journal of Neurochemistry, 2002Co-Authors: Shiro Fukuda, Kazuki Harada, Mitoshi Kunimatsu, Takefumi Sakabe, Kenichi YoshidaAbstract:Abstract: A membrane cytoskeletal protein, Fodrin, is a substrate for a Ca2+-dependent protease, calpain. It remains unknown whether μ-calpain or m-calpain is involved in the proteolysis of either α- or β-Fodrin and in what subcellular localization during ischemia and reperfusion of the brain. To address these issues, we examined the distribution of Fodrin and calpain and the activities of calpain and calpastatin (endogenous calpain inhibitor) in the same subcellular fractions. Rat forebrain was subjected to ischemia by a combination of occlusion of both carotid arteries and systemic hypotension, whereas reperfusion was induced by releasing the occlusion. Immunoblotting, activity measurement, and casein zymography did not detect the presence of μ-calpain or a significant change of m-calpain level after ischemia or reperfusion. However, casein zymography revealed a unique Ca2+-dependent protease that was eluted with both 0.18 and 0.40 M NaCl from a DEAE-cellulose column. α- and β-Fodrins and m-calpain were found to be rich in the synaptosomal, nuclear, and cytosolic subfractions by immunoblotting analysis. Reperfusion (60 min) following ischemia (30 min) induced selective proteolysis of α-Fodrin, which was inhibited by a calpain inhibitor, acetylleucylleucylnorleucinal (400 µM, 1 ml, i.v.). The μ-calpain-specific fragment of β-Fodrin was not generated during ischemia-reperfusion, supporting the possibility of the involvement of m-calpain rather than μ-calpain in the α-Fodrin proteolysis.
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postischemic reperfusion induces α Fodrin proteolysis by m calpain in the synaptosome and nucleus in rat brain
Journal of Neurochemistry, 2002Co-Authors: Shiro Fukuda, Kazuki Harada, Mitoshi Kunimatsu, Takefumi Sakabe, Kenichi YoshidaAbstract:A membrane cytoskeletal protein, Fodrin, is a substrate for a Ca2+-dependent protease, calpain. It remains unknown whether mu-calpain or m-calpain is involved in the proteolysis of either alpha- or beta-Fodrin and in what subcellular localization during ischemia and reperfusion of the brain. To address these issues, we examined the distribution of Fodrin and calpain and the activities of calpain and calpastatin (endogenous calpain inhibitor) in the same subcellular fractions. Rat forebrain was subjected to ischemia by a combination of occlusion of both carotid arteries and systemic hypotension, whereas reperfusion was induced by releasing the occlusion. Immunoblotting, activity measurement, and casein zymography did not detect the presence of mu-calpain or a significant change of m-calpain level after ischemia or reperfusion. However, casein zymography revealed a unique Ca2+-dependent protease that was eluted with both 0.18 and 0.40 M NaCl from a DEAE-cellulose column. Alpha- and beta-Fodrins and m-calpain were found to be rich in the synaptosomal, nuclear, and cytosolic subfractions by immunoblotting analysis. Reperfusion (60 min) following ischemia (30 min) induced selective proteolysis of alpha-Fodrin, which was inhibited by a calpain inhibitor, acetylleucylleucylnorleucinal (400 microM, 1 ml, i.v.). The mu-calpain-specific fragment of beta-Fodrin was not generated during ischemia-reperfusion, supporting the possibility of the involvement of m-calpain rather than mu-calpain in the alpha-Fodrin proteolysis.
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nitric oxide promotes germ cell necrosis in the delayed phase after experimental testicular torsion of rat
Biology of Reproduction, 2001Co-Authors: Koji Shiraishi, Katsusuke Naito, Kenichi YoshidaAbstract:The purpose of this study is to determine whether inducible nitric oxide synthase (iNOS) is involved in the pathogenesis of testicular ischemia-reperfusion (I/R) injury in association with germ cell death, through either necrosis or apoptosis. Western blot analysis showed that iNOS expression was markedly increased 1 h after ischemia, and was accompanied by a huge nitric oxide (NO) production, as measured by the Griess method, with a peak at 48 h of reperfusion. Immunohistochemistry showed that iNOS was expressed predominantly in the macrophage-like cells infiltrated in the interstitial tissues of the testis. Intraperitoneal injection of aminoguanidine (AMG) (400 mg/day), the inhibitor of iNOS, reduced NO production by 57.7% at 96 h of reperfusion. Calpain activation and proteolysis of a-Fodrin induced by I/R were inhibited by AMG. Germ cell apoptosis was demonstrated by in situ TUNEL and DNA fragmentation on agarose gel electrophoresis. Germ cell apoptosis was maximally induced at 24 h of reperfusion, and was not inhibited by AMG. NO produced by iNOS in the delayed phase of reperfusion promoted a-Fodrin proteolysis, which is closely associated with necrosis. Inducible NOS inhibition combined with calpain inhibition may improve impaired spermatogenesis after testicular torsion. apoptosis, nitric oxide, testis
Paul F. Pilch - One of the best experts on this subject based on the ideXlab platform.
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role of insulin dependent cortical Fodrin spectrin remodeling in glucose transporter 4 translocation in rat adipocytes
Molecular Biology of the Cell, 2006Co-Authors: Libin Liu, Mark P. Jedrychowski, Steven P. Gygi, Paul F. PilchAbstract:Fodrin or nonerythroid spectrin is an abundant component of the cortical cytoskeletal network in rat adipocytes. Fodrin has a highly punctate distribution in resting cells, and insulin causes a dramatic remodeling of Fodrin to a more diffuse pattern. Insulin-mediated remodeling of actin occurs to a lesser extent than does that of Fodrin. We show that Fodrin interacts with the t-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) syntaxin 4, and this interaction is increased by insulin stimulation and decreased by prior latrunculin A treatment. Latrunculin A disrupts all actin filaments, inhibits glucose transporter 4 (GLUT4) translocation, and causes Fodrin to partially redistribute from the plasma membrane to the cytosol. In contrast, cytochalasin D disrupts only the short actin filament signal, and cytochalasin D neither inhibits GLUT4 translocation nor Fodrin redistribution in adipocytes. Together, our data suggest that insulin induces remodeling of the Fodrin-actin network, which is required for the fusion of GLUT4 storage vesicles with the plasma membrane by permitting their access to the t-SNARE syntaxin 4.
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Role of Insulin-dependent Cortical Fodrin/Spectrin Remodeling in Glucose Transporter 4 Translocation in Rat Adipocytes
Molecular biology of the cell, 2006Co-Authors: Libin Liu, Mark P. Jedrychowski, Steven P. Gygi, Paul F. PilchAbstract:Fodrin or nonerythroid spectrin is an abundant component of the cortical cytoskeletal network in rat adipocytes. Fodrin has a highly punctate distribution in resting cells, and insulin causes a dramatic remodeling of Fodrin to a more diffuse pattern. Insulin-mediated remodeling of actin occurs to a lesser extent than does that of Fodrin. We show that Fodrin interacts with the t-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) syntaxin 4, and this interaction is increased by insulin stimulation and decreased by prior latrunculin A treatment. Latrunculin A disrupts all actin filaments, inhibits glucose transporter 4 (GLUT4) translocation, and causes Fodrin to partially redistribute from the plasma membrane to the cytosol. In contrast, cytochalasin D disrupts only the short actin filament signal, and cytochalasin D neither inhibits GLUT4 translocation nor Fodrin redistribution in adipocytes. Together, our data suggest that insulin induces remodeling of the Fodrin-actin network, which is required for the fusion of GLUT4 storage vesicles with the plasma membrane by permitting their access to the t-SNARE syntaxin 4.
Douglas R. Green - One of the best experts on this subject based on the ideXlab platform.
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cytochrome c activation of cpp32 like proteolysis plays a critical role in a xenopus cell free apoptosis system
The EMBO Journal, 1997Co-Authors: Ruth M Kluck, Seamus J Martin, Douglas R. Green, Brian M Hoffman, Jian S Zhou, Donald D NewmeyerAbstract:In a cell-free system based on Xenopus egg extracts, Bcl-2 blocks apoptotic activity by preventing cytochrome c release from mitochondria. We now describe in detail the crucial role of cytochrome c in this system. The mitochondrial fraction, when incubated with cytosol, releases cytochrome c. Cytochrome c in turn induces the activation of protease(s) resembling caspase-3 (CPP32), leading to downstream apoptotic events, including the cleavage of Fodrin and lamin B1. CPP32-like protease activity plays an essential role in this system, as the caspase inhibitor, Ac-DEVD-CHO, strongly inhibited Fodrin and lamin B1 cleavage, as well as nuclear morphology changes. Cytochrome c preparations from various vertebrate species, but not from Saccharomyces cerevisiae, were able to initiate all signs of apoptosis. Cytochrome c by itself was unable to process the precursor form of CPP32; the presence of cytosol was required. The electron transport activity of cytochrome c is not required for its pro-apoptotic function, as Cu- and Zn-substituted cytochrome c had strong pro-apoptotic activity, despite being redox-inactive. However, certain structural features of the molecule were required for this activity. Thus, in the Xenopus cell-free system, cytosol-dependent mitochondrial release of cytochrome c induces apoptosis by activating CPP32-like caspases, via unknown cytosolic factors.
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cytochrome c activation of cpp32 like proteolysis plays a critical role in a xenopus cell free apoptosis system
The EMBO Journal, 1997Co-Authors: Ruth M Kluck, Seamus J Martin, Douglas R. Green, Brian M Hoffman, Jian S Zhou, Donald D NewmeyerAbstract:In a cell-free system based on Xenopus egg extracts, Bcl-2 blocks apoptotic activity by preventing cytochrome c release from mitochondria. We now describe in detail the crucial role of cytochrome c in this system. The mitochondrial fraction, when incubated with cytosol, releases cytochrome c. Cytochrome c in turn induces the activation of protease(s) resembling caspase-3 (CPP32), leading to downstream apoptotic events, including the cleavage of Fodrin and lamin B1. CPP32-like protease activity plays an essential role in this system, as the caspase inhibitor, Ac-DEVD-CHO, strongly inhibited Fodrin and lamin B1 cleavage, as well as nuclear morphology changes. Cytochrome c preparations from various vertebrate species, but not from Saccharomyces cerevisiae, were able to initiate all signs of apoptosis. Cytochrome c by itself was unable to process the precursor form of CPP32; the presence of cytosol was required. The electron transport activity of cytochrome c is not required for its pro-apoptotic function, as Cu- and Zn-substituted cytochrome c had strong pro-apoptotic activity, despite being redox-inactive. However, certain structural features of the molecule were required for this activity. Thus, in the Xenopus cell-free system, cytosol-dependent mitochondrial release of cytochrome c induces apoptosis by activating CPP32-like caspases, via unknown cytosolic factors.
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phosphatidylserine externalization during cd95 induced apoptosis of cells and cytoplasts requires ice ced 3 protease activity
Journal of Biological Chemistry, 1996Co-Authors: Seamus J Martin, Geraldine A Obrien, Deborah Finucane, Gustavo P Amarantemendes, Douglas R. GreenAbstract:Phosphatidylserine (PS), a lipid normally confined to the inner leaflet of the plasma membrane, is exported to the outer plasma membrane leaflet during apoptosis to serve as a trigger for recognition of apoptotic cells by phagocytes. The mechanism of PS export during apoptosis is not known nor is it clear whether the nuclear changes that typify apoptosis contribute in any way to this event. Here, we demonstrate that ligation of the CD95 (Fas/APO-1) molecule on Jurkat cytoplasts induces dramatic PS externalization similar to that observed during apoptosis of intact cells. Apoptosis of both cells and cytoplasts was associated with proteolytic processing of CPP32, a member of the interleukin-1beta converting enzyme (ICE)/CED-3 protease family, to its active form. Fodrin, a component of the cortical cytoskeleton, also underwent proteolytic cleavage during apoptosis of both cytoplasts and intact cells. Strikingly, CPP32 activation, Fodrin proteolysis, and PS externalization were all inhibited in the presence of peptide inhibitors of ICE/CED-3 family proteases. These data provide strong support for the notion that the cell death machinery is extranuclear and is likely to be comprised of one or more members of the ICE/CED-3 family and that activation of this machinery does not require nuclear participation.
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proteolysis of Fodrin non erythroid spectrin during apoptosis
Journal of Biological Chemistry, 1995Co-Authors: Seamus J Martin, Geraldine A Obrien, Walter K Nishioka, Anne J Mcgahon, Artin Mahboubi, Takaomi C Saido, Douglas R. GreenAbstract:Abstract Several recent studies have implicated proteases as important triggers of apoptosis. Thus far, substrates that are cleaved during apoptosis have been elusive. In this report we demonstrate that cleavage of α-Fodrin (non-erythroid spectrin) accompanies apoptosis, induced by activation via the CD3/T cell receptor complex in a murine T cell hybridoma, ligation of the Fas (CD95) molecule on a human T cell lymphoma line and other Fas-expressing cells, or treatment of cells with staurosporine, dexamethasone, or synthetic ceramide. Furthermore, inhibition of activation-induced apoptosis by pretreatment of T hybridoma cells with antisense oligonucleotides directed against c-myc also inhibited Fodrin proteolysis, confirming that this cleavage process is tightly coupled to apoptosis. Fodrin cleavage during apoptosis may have implications for the membrane blebbing seen during this process.
Seamus J Martin - One of the best experts on this subject based on the ideXlab platform.
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cytochrome c activation of cpp32 like proteolysis plays a critical role in a xenopus cell free apoptosis system
The EMBO Journal, 1997Co-Authors: Ruth M Kluck, Seamus J Martin, Douglas R. Green, Brian M Hoffman, Jian S Zhou, Donald D NewmeyerAbstract:In a cell-free system based on Xenopus egg extracts, Bcl-2 blocks apoptotic activity by preventing cytochrome c release from mitochondria. We now describe in detail the crucial role of cytochrome c in this system. The mitochondrial fraction, when incubated with cytosol, releases cytochrome c. Cytochrome c in turn induces the activation of protease(s) resembling caspase-3 (CPP32), leading to downstream apoptotic events, including the cleavage of Fodrin and lamin B1. CPP32-like protease activity plays an essential role in this system, as the caspase inhibitor, Ac-DEVD-CHO, strongly inhibited Fodrin and lamin B1 cleavage, as well as nuclear morphology changes. Cytochrome c preparations from various vertebrate species, but not from Saccharomyces cerevisiae, were able to initiate all signs of apoptosis. Cytochrome c by itself was unable to process the precursor form of CPP32; the presence of cytosol was required. The electron transport activity of cytochrome c is not required for its pro-apoptotic function, as Cu- and Zn-substituted cytochrome c had strong pro-apoptotic activity, despite being redox-inactive. However, certain structural features of the molecule were required for this activity. Thus, in the Xenopus cell-free system, cytosol-dependent mitochondrial release of cytochrome c induces apoptosis by activating CPP32-like caspases, via unknown cytosolic factors.
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cytochrome c activation of cpp32 like proteolysis plays a critical role in a xenopus cell free apoptosis system
The EMBO Journal, 1997Co-Authors: Ruth M Kluck, Seamus J Martin, Douglas R. Green, Brian M Hoffman, Jian S Zhou, Donald D NewmeyerAbstract:In a cell-free system based on Xenopus egg extracts, Bcl-2 blocks apoptotic activity by preventing cytochrome c release from mitochondria. We now describe in detail the crucial role of cytochrome c in this system. The mitochondrial fraction, when incubated with cytosol, releases cytochrome c. Cytochrome c in turn induces the activation of protease(s) resembling caspase-3 (CPP32), leading to downstream apoptotic events, including the cleavage of Fodrin and lamin B1. CPP32-like protease activity plays an essential role in this system, as the caspase inhibitor, Ac-DEVD-CHO, strongly inhibited Fodrin and lamin B1 cleavage, as well as nuclear morphology changes. Cytochrome c preparations from various vertebrate species, but not from Saccharomyces cerevisiae, were able to initiate all signs of apoptosis. Cytochrome c by itself was unable to process the precursor form of CPP32; the presence of cytosol was required. The electron transport activity of cytochrome c is not required for its pro-apoptotic function, as Cu- and Zn-substituted cytochrome c had strong pro-apoptotic activity, despite being redox-inactive. However, certain structural features of the molecule were required for this activity. Thus, in the Xenopus cell-free system, cytosol-dependent mitochondrial release of cytochrome c induces apoptosis by activating CPP32-like caspases, via unknown cytosolic factors.
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phosphatidylserine externalization during cd95 induced apoptosis of cells and cytoplasts requires ice ced 3 protease activity
Journal of Biological Chemistry, 1996Co-Authors: Seamus J Martin, Geraldine A Obrien, Deborah Finucane, Gustavo P Amarantemendes, Douglas R. GreenAbstract:Phosphatidylserine (PS), a lipid normally confined to the inner leaflet of the plasma membrane, is exported to the outer plasma membrane leaflet during apoptosis to serve as a trigger for recognition of apoptotic cells by phagocytes. The mechanism of PS export during apoptosis is not known nor is it clear whether the nuclear changes that typify apoptosis contribute in any way to this event. Here, we demonstrate that ligation of the CD95 (Fas/APO-1) molecule on Jurkat cytoplasts induces dramatic PS externalization similar to that observed during apoptosis of intact cells. Apoptosis of both cells and cytoplasts was associated with proteolytic processing of CPP32, a member of the interleukin-1beta converting enzyme (ICE)/CED-3 protease family, to its active form. Fodrin, a component of the cortical cytoskeleton, also underwent proteolytic cleavage during apoptosis of both cytoplasts and intact cells. Strikingly, CPP32 activation, Fodrin proteolysis, and PS externalization were all inhibited in the presence of peptide inhibitors of ICE/CED-3 family proteases. These data provide strong support for the notion that the cell death machinery is extranuclear and is likely to be comprised of one or more members of the ICE/CED-3 family and that activation of this machinery does not require nuclear participation.
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proteolysis of Fodrin non erythroid spectrin during apoptosis
Journal of Biological Chemistry, 1995Co-Authors: Seamus J Martin, Geraldine A Obrien, Walter K Nishioka, Anne J Mcgahon, Artin Mahboubi, Takaomi C Saido, Douglas R. GreenAbstract:Abstract Several recent studies have implicated proteases as important triggers of apoptosis. Thus far, substrates that are cleaved during apoptosis have been elusive. In this report we demonstrate that cleavage of α-Fodrin (non-erythroid spectrin) accompanies apoptosis, induced by activation via the CD3/T cell receptor complex in a murine T cell hybridoma, ligation of the Fas (CD95) molecule on a human T cell lymphoma line and other Fas-expressing cells, or treatment of cells with staurosporine, dexamethasone, or synthetic ceramide. Furthermore, inhibition of activation-induced apoptosis by pretreatment of T hybridoma cells with antisense oligonucleotides directed against c-myc also inhibited Fodrin proteolysis, confirming that this cleavage process is tightly coupled to apoptosis. Fodrin cleavage during apoptosis may have implications for the membrane blebbing seen during this process.
Libin Liu - One of the best experts on this subject based on the ideXlab platform.
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role of insulin dependent cortical Fodrin spectrin remodeling in glucose transporter 4 translocation in rat adipocytes
Molecular Biology of the Cell, 2006Co-Authors: Libin Liu, Mark P. Jedrychowski, Steven P. Gygi, Paul F. PilchAbstract:Fodrin or nonerythroid spectrin is an abundant component of the cortical cytoskeletal network in rat adipocytes. Fodrin has a highly punctate distribution in resting cells, and insulin causes a dramatic remodeling of Fodrin to a more diffuse pattern. Insulin-mediated remodeling of actin occurs to a lesser extent than does that of Fodrin. We show that Fodrin interacts with the t-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) syntaxin 4, and this interaction is increased by insulin stimulation and decreased by prior latrunculin A treatment. Latrunculin A disrupts all actin filaments, inhibits glucose transporter 4 (GLUT4) translocation, and causes Fodrin to partially redistribute from the plasma membrane to the cytosol. In contrast, cytochalasin D disrupts only the short actin filament signal, and cytochalasin D neither inhibits GLUT4 translocation nor Fodrin redistribution in adipocytes. Together, our data suggest that insulin induces remodeling of the Fodrin-actin network, which is required for the fusion of GLUT4 storage vesicles with the plasma membrane by permitting their access to the t-SNARE syntaxin 4.
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Role of Insulin-dependent Cortical Fodrin/Spectrin Remodeling in Glucose Transporter 4 Translocation in Rat Adipocytes
Molecular biology of the cell, 2006Co-Authors: Libin Liu, Mark P. Jedrychowski, Steven P. Gygi, Paul F. PilchAbstract:Fodrin or nonerythroid spectrin is an abundant component of the cortical cytoskeletal network in rat adipocytes. Fodrin has a highly punctate distribution in resting cells, and insulin causes a dramatic remodeling of Fodrin to a more diffuse pattern. Insulin-mediated remodeling of actin occurs to a lesser extent than does that of Fodrin. We show that Fodrin interacts with the t-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) syntaxin 4, and this interaction is increased by insulin stimulation and decreased by prior latrunculin A treatment. Latrunculin A disrupts all actin filaments, inhibits glucose transporter 4 (GLUT4) translocation, and causes Fodrin to partially redistribute from the plasma membrane to the cytosol. In contrast, cytochalasin D disrupts only the short actin filament signal, and cytochalasin D neither inhibits GLUT4 translocation nor Fodrin redistribution in adipocytes. Together, our data suggest that insulin induces remodeling of the Fodrin-actin network, which is required for the fusion of GLUT4 storage vesicles with the plasma membrane by permitting their access to the t-SNARE syntaxin 4.