The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Michael P Sheetz - One of the best experts on this subject based on the ideXlab platform.
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Endoplasmic spreading requires coalescence of vimentin intermediate filaments at force bearing adhesions
Molecular Biology of the Cell, 2013Co-Authors: Christopher D Lynch, Andre M Lazar, Thomas Iskratsch, Xian Zhang, Michael P SheetzAbstract:Interaction of vimentin filaments (vIFs) and force-bearing adhesions is essential for Endoplasm spreading. For adhesions to be connected to a contractile network involved in Endoplasm spreading, vI...
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Endoplasmic spreading requires coalescence of vimentin intermediate filaments at force bearing adhesions
Molecular Biology of the Cell, 2013Co-Authors: Christopher D Lynch, Andre M Lazar, Thomas Iskratsch, Xian Zhang, Michael P SheetzAbstract:: For cells to develop long-range forces and carry materials to the periphery, the microtubule and organelle-rich region at the center of the cell-the Endoplasm-needs to extend to near the cell edge. Depletion of the actin cross-linking protein filamin A (FlnA) causes a collapse of the Endoplasm into a sphere around the nucleus of fibroblasts and disruption of matrix adhesions, indicating that FlnA is involved in Endoplasmic spreading and adhesion growth. Here, we report that treatment with the calpain inhibitor N-[N-(N-acetyl-l-leucyl)-l-leucyl]-l-norleucine (ALLN) restores Endoplasmic spreading as well as focal adhesion (FA) growth on fibronectin-coated surfaces in a Fln-depleted background. Addback of calpain-uncleavable talin, not full-length talin, achieves a similar effect in Fln-depleted cells and indicates a crucial role for talin in Endoplasmic spreading. Because FA maturation involves the vimentin intermediate filament (vIF) network, we also examined the role of vIFs in Endoplasmic spreading. Wild-type cells expressing a vimentin variant incapable of polymerization exhibit deficient Endoplasmic spreading as well as defects in FA growth. ALLN treatment restores FA growth despite the lack of vIFs but does not restore Endoplasmic spreading, implying that vIFs are essential for Endoplasm spreading. Consistent with that hypothesis, vIFs are always displaced from adhesions when the Endoplasm does not spread. In Fln-depleted cells, vIFs extend beyond adhesions, nearly to the cell edge. Finally, inhibiting myosin II-mediated contraction blocks Endoplasmic spreading and adhesion growth. Thus we propose a model in which myosin II-mediated forces and coalescence of vIFs at mature FAs are required for Endoplasmic spreading.
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filamin depletion blocks Endoplasmic spreading and destabilizes force bearing adhesions
Molecular Biology of the Cell, 2011Co-Authors: Christopher D Lynch, Andre M Lazar, Michael P Sheetz, Nils C Gauthier, Nicolas Biais, Pere Rocacusachs, Chenghan YuAbstract:Cell motility is an essential process that depends on a coherent, cross-linked actin cytoskeleton that physically coordinates the actions of numerous structural and signaling molecules. The actin cross-linking protein, filamin (Fln), has been implicated in the support of three-dimensional cortical actin networks capable of both maintaining cellular integrity and withstanding large forces. Although numerous studies have examined cells lacking one of the multiple Fln isoforms, compensatory mechanisms can mask novel phenotypes only observable by further Fln depletion. Indeed, shRNA-mediated knockdown of FlnA in FlnB–/– mouse embryonic fibroblasts (MEFs) causes a novel Endoplasmic spreading deficiency as detected by Endoplasmic reticulum markers. Microtubule (MT) extension rates are also decreased but not by peripheral actin flow, because this is also decreased in the Fln-depleted system. Additionally, Fln-depleted MEFs exhibit decreased adhesion stability that appears in increased ruffling of the cell edge, reduced adhesion size, transient traction forces, and decreased stress fibers. FlnA–/– MEFs, but not FlnB–/– MEFs, also show a moderate defect in Endoplasm spreading, characterized by initial extension followed by abrupt retractions and stress fiber fracture. FlnA localizes to actin linkages surrounding the Endoplasm, adhesions, and stress fibers. Thus we suggest that Flns have a major role in the maintenance of actin-based mechanical linkages that enable Endoplasmic spreading and MT extension as well as sustained traction forces and mature focal adhesions.
Christopher D Lynch - One of the best experts on this subject based on the ideXlab platform.
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Endoplasmic spreading requires coalescence of vimentin intermediate filaments at force bearing adhesions
Molecular Biology of the Cell, 2013Co-Authors: Christopher D Lynch, Andre M Lazar, Thomas Iskratsch, Xian Zhang, Michael P SheetzAbstract:Interaction of vimentin filaments (vIFs) and force-bearing adhesions is essential for Endoplasm spreading. For adhesions to be connected to a contractile network involved in Endoplasm spreading, vI...
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Endoplasmic spreading requires coalescence of vimentin intermediate filaments at force bearing adhesions
Molecular Biology of the Cell, 2013Co-Authors: Christopher D Lynch, Andre M Lazar, Thomas Iskratsch, Xian Zhang, Michael P SheetzAbstract:: For cells to develop long-range forces and carry materials to the periphery, the microtubule and organelle-rich region at the center of the cell-the Endoplasm-needs to extend to near the cell edge. Depletion of the actin cross-linking protein filamin A (FlnA) causes a collapse of the Endoplasm into a sphere around the nucleus of fibroblasts and disruption of matrix adhesions, indicating that FlnA is involved in Endoplasmic spreading and adhesion growth. Here, we report that treatment with the calpain inhibitor N-[N-(N-acetyl-l-leucyl)-l-leucyl]-l-norleucine (ALLN) restores Endoplasmic spreading as well as focal adhesion (FA) growth on fibronectin-coated surfaces in a Fln-depleted background. Addback of calpain-uncleavable talin, not full-length talin, achieves a similar effect in Fln-depleted cells and indicates a crucial role for talin in Endoplasmic spreading. Because FA maturation involves the vimentin intermediate filament (vIF) network, we also examined the role of vIFs in Endoplasmic spreading. Wild-type cells expressing a vimentin variant incapable of polymerization exhibit deficient Endoplasmic spreading as well as defects in FA growth. ALLN treatment restores FA growth despite the lack of vIFs but does not restore Endoplasmic spreading, implying that vIFs are essential for Endoplasm spreading. Consistent with that hypothesis, vIFs are always displaced from adhesions when the Endoplasm does not spread. In Fln-depleted cells, vIFs extend beyond adhesions, nearly to the cell edge. Finally, inhibiting myosin II-mediated contraction blocks Endoplasmic spreading and adhesion growth. Thus we propose a model in which myosin II-mediated forces and coalescence of vIFs at mature FAs are required for Endoplasmic spreading.
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filamin depletion blocks Endoplasmic spreading and destabilizes force bearing adhesions
Molecular Biology of the Cell, 2011Co-Authors: Christopher D Lynch, Andre M Lazar, Michael P Sheetz, Nils C Gauthier, Nicolas Biais, Pere Rocacusachs, Chenghan YuAbstract:Cell motility is an essential process that depends on a coherent, cross-linked actin cytoskeleton that physically coordinates the actions of numerous structural and signaling molecules. The actin cross-linking protein, filamin (Fln), has been implicated in the support of three-dimensional cortical actin networks capable of both maintaining cellular integrity and withstanding large forces. Although numerous studies have examined cells lacking one of the multiple Fln isoforms, compensatory mechanisms can mask novel phenotypes only observable by further Fln depletion. Indeed, shRNA-mediated knockdown of FlnA in FlnB–/– mouse embryonic fibroblasts (MEFs) causes a novel Endoplasmic spreading deficiency as detected by Endoplasmic reticulum markers. Microtubule (MT) extension rates are also decreased but not by peripheral actin flow, because this is also decreased in the Fln-depleted system. Additionally, Fln-depleted MEFs exhibit decreased adhesion stability that appears in increased ruffling of the cell edge, reduced adhesion size, transient traction forces, and decreased stress fibers. FlnA–/– MEFs, but not FlnB–/– MEFs, also show a moderate defect in Endoplasm spreading, characterized by initial extension followed by abrupt retractions and stress fiber fracture. FlnA localizes to actin linkages surrounding the Endoplasm, adhesions, and stress fibers. Thus we suggest that Flns have a major role in the maintenance of actin-based mechanical linkages that enable Endoplasmic spreading and MT extension as well as sustained traction forces and mature focal adhesions.
M. Kikuyama - One of the best experts on this subject based on the ideXlab platform.
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Bidirectional flow of Endoplasm inPhysarum plasmodium under centrifugal acceleration
Protoplasma, 1994Co-Authors: E. Kamitsubo, M. KikuyamaAbstract:The behavior of cytoplasmic streaming in plasmodial strand ofPhysarum polycephalum was studied under centrifugal acceleration using a centrifuge microscope of the stroboscopic type. Cytoplasmic streaming in the plasmodium was greatly affected by changes in the acceleration. The Endoplasmic flow in the centrifugal direction was accelerated, while that in the centripetal was retarded, by centrifugal acceleration. The centrifugal acceleration required to stop the Endoplasmic flow in the centripetal direction did not cause total cessation of streaming but always induced a bidirectional flow of Endoplasm in one and the same strand. Each profile of velocity distribution of the bidirectional flow was both parabola with flattened apex. One possible cause of the bidirectional flow is discussed.
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immobilization of Endoplasm flowing contiguous to the actin cables upon electrical stimulus in nitella internodes
Protoplasma, 1992Co-Authors: E. Kamitsubo, M. KikuyamaAbstract:Using a stroboscopic centrifuge microscope, we demonstrated that, when actin cables (=bundles of F-actin) had been previously removed locally from the cell cortex ofNitella internodes, the passively flowing Endoplasm found there under centrifugal force did not stop at all upon electrical stimulus, while the actively flowing Endoplasm contiguous to the actin cables at the normal cell cortex promptly stopped following the stimulus and was immobilized for several seconds. The results present evidence that, upon electrical stimulus, the presence of actin cables is required to immobilize the Endoplasm flowing contiguous to the actin cables in a state that resists displacement by centrifugal force.
Chaoshu Tang - One of the best experts on this subject based on the ideXlab platform.
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inhibition of Endoplasm reticulum stress by ghrelin protects against ischemia reperfusion injury in rat heart
Peptides, 2009Co-Authors: Gaigai Zhang, Xu Teng, Yue Liu, Yan Cai, Yebo Zhou, Xiaohui Duan, Junqiu Song, Yi Shi, Chaoshu TangAbstract:Abstract Ghrelin is a multi-functional polypeptide with cardiovascular protective effects. We aimed to explore whether the cardioprotective effect of ghrelin is mediated by inhibiting myocardial Endoplasmic reticulum stress (ERS). A Langendorff model of isolated rat heart was used with ischemia/reperfusion (I/R; 40/120 min). Cardiac function was monitored, and histomorphologic features, degree of myocardial injury, level of ERS markers, and number of apoptotic cardiomyocytes were determined. Compared with control group, the I/R group showed significantly decreased cardiac function, seriously damaged myocardial tissue, increased number of apoptotic cells, and overexpression of mRNA and protein of ERS markers. However, preadministration of ghrelin in vivo (10 −8 mol/kg, intraperitoneal injection, every 12 h, twice in all) greatly ameliorated the damaged heart function, attenuated myocardial injury and apoptosis, and decreased the expression of ERS markers: it decreased the mRNA and protein levels of glucose-regulated protein78 (GRP78) and C/EBP homologous protein (CHOP), with reduced caspase-12 protein expression. Furthermore, in vitro, ghrelin directly inhibited the myocardial ERS response induced by tunicamycin or dithiothreitol in rat cardiac tissue. Ghrelin could protect the heart against I/R injury, at least in part, through inhibiting myocardial ERS.
Andre M Lazar - One of the best experts on this subject based on the ideXlab platform.
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Endoplasmic spreading requires coalescence of vimentin intermediate filaments at force bearing adhesions
Molecular Biology of the Cell, 2013Co-Authors: Christopher D Lynch, Andre M Lazar, Thomas Iskratsch, Xian Zhang, Michael P SheetzAbstract:Interaction of vimentin filaments (vIFs) and force-bearing adhesions is essential for Endoplasm spreading. For adhesions to be connected to a contractile network involved in Endoplasm spreading, vI...
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Endoplasmic spreading requires coalescence of vimentin intermediate filaments at force bearing adhesions
Molecular Biology of the Cell, 2013Co-Authors: Christopher D Lynch, Andre M Lazar, Thomas Iskratsch, Xian Zhang, Michael P SheetzAbstract:: For cells to develop long-range forces and carry materials to the periphery, the microtubule and organelle-rich region at the center of the cell-the Endoplasm-needs to extend to near the cell edge. Depletion of the actin cross-linking protein filamin A (FlnA) causes a collapse of the Endoplasm into a sphere around the nucleus of fibroblasts and disruption of matrix adhesions, indicating that FlnA is involved in Endoplasmic spreading and adhesion growth. Here, we report that treatment with the calpain inhibitor N-[N-(N-acetyl-l-leucyl)-l-leucyl]-l-norleucine (ALLN) restores Endoplasmic spreading as well as focal adhesion (FA) growth on fibronectin-coated surfaces in a Fln-depleted background. Addback of calpain-uncleavable talin, not full-length talin, achieves a similar effect in Fln-depleted cells and indicates a crucial role for talin in Endoplasmic spreading. Because FA maturation involves the vimentin intermediate filament (vIF) network, we also examined the role of vIFs in Endoplasmic spreading. Wild-type cells expressing a vimentin variant incapable of polymerization exhibit deficient Endoplasmic spreading as well as defects in FA growth. ALLN treatment restores FA growth despite the lack of vIFs but does not restore Endoplasmic spreading, implying that vIFs are essential for Endoplasm spreading. Consistent with that hypothesis, vIFs are always displaced from adhesions when the Endoplasm does not spread. In Fln-depleted cells, vIFs extend beyond adhesions, nearly to the cell edge. Finally, inhibiting myosin II-mediated contraction blocks Endoplasmic spreading and adhesion growth. Thus we propose a model in which myosin II-mediated forces and coalescence of vIFs at mature FAs are required for Endoplasmic spreading.
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filamin depletion blocks Endoplasmic spreading and destabilizes force bearing adhesions
Molecular Biology of the Cell, 2011Co-Authors: Christopher D Lynch, Andre M Lazar, Michael P Sheetz, Nils C Gauthier, Nicolas Biais, Pere Rocacusachs, Chenghan YuAbstract:Cell motility is an essential process that depends on a coherent, cross-linked actin cytoskeleton that physically coordinates the actions of numerous structural and signaling molecules. The actin cross-linking protein, filamin (Fln), has been implicated in the support of three-dimensional cortical actin networks capable of both maintaining cellular integrity and withstanding large forces. Although numerous studies have examined cells lacking one of the multiple Fln isoforms, compensatory mechanisms can mask novel phenotypes only observable by further Fln depletion. Indeed, shRNA-mediated knockdown of FlnA in FlnB–/– mouse embryonic fibroblasts (MEFs) causes a novel Endoplasmic spreading deficiency as detected by Endoplasmic reticulum markers. Microtubule (MT) extension rates are also decreased but not by peripheral actin flow, because this is also decreased in the Fln-depleted system. Additionally, Fln-depleted MEFs exhibit decreased adhesion stability that appears in increased ruffling of the cell edge, reduced adhesion size, transient traction forces, and decreased stress fibers. FlnA–/– MEFs, but not FlnB–/– MEFs, also show a moderate defect in Endoplasm spreading, characterized by initial extension followed by abrupt retractions and stress fiber fracture. FlnA localizes to actin linkages surrounding the Endoplasm, adhesions, and stress fibers. Thus we suggest that Flns have a major role in the maintenance of actin-based mechanical linkages that enable Endoplasmic spreading and MT extension as well as sustained traction forces and mature focal adhesions.