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Christine Chaponnier - One of the best experts on this subject based on the ideXlab platform.
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Expression and function of alpha-Smooth Muscle Actin during embryonic-stem-cell-derived cardiomyocyte differentiation.
Journal of Cell Science, 2007Co-Authors: Sophie Clement, Christine Chaponnier, Michael Stouffs, Esther Bettiol, Sandy Kampf, Karl-heinz Krause, Marisa JaconiAbstract:Three alpha-Muscle Actin isoforms are sequentially expressed during in vivo cardiac development. alpha-Smooth Muscle Actin is first and transiently expressed, followed by alpha-skeletal and finally alpha-cardiac Actin. The significance of these transitions in Actin gene expression during myogenesis remains to be determined. To understand whether Actin isoforms have specific functions during cardiac development and cardiomyocyte contractility, we have hampered alpha-Smooth Muscle and alpha-skeletal Actin expression and organization during embryonic stem cell differentiation towards cardiomyocyte. We show that the sequence of Actin isoform expression displays similar pattern in the in vitro model and in mouse heart embryogenesis. Treatment with an interfering fusion peptide containing the N-terminal sequence of alpha-Smooth Muscle Actin during a time window preceding spontaneous beating, prevents proper cardiac sarcomyogenesis, whereas alpha-skeletal Actin-fusion peptide has no effect. Knockdown of alpha-Smooth Muscle Actin in embryonic stem cells using RNA interference also affects cardiac differentiation. The application of both fusion peptides on beating embryoid bodies impairs frequency. These results suggest specific functional activities for Actin isoforms in cardiogenesis and cardiomyocyte contractility.
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the n terminal ac eeed sequence plays a role in alpha Smooth Muscle Actin incorporation into stress fibers
Journal of Cell Science, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:We have previously shown that the N-terminal sequence AcEEED of alpha-Smooth-Muscle Actin causes the loss of alpha-Smooth-Muscle Actin from stress fibers and a decrease in cell contractility when introduced in myofibroblasts as a cell-penetrating fusion peptide. Here, we have investigated the function of this sequence on stress fiber organization in living cells, using enhanced green fluorescent protein (EGFP)-tagged alpha-Smooth-Muscle Actin. The fusion peptide provokes the gradual disappearance of EGFP fluorescence of alpha-Smooth-Muscle Actin from stress fibers and the formation of hitherto unknown rod-like structures. In addition to alpha-Smooth-Muscle Actin, these structures contain cytoplasmic Actins, gelsolin and cofilin but not other major Actin-binding proteins. These rod-like structures are also visible in wild-type fibroblasts during normal cell spreading, suggesting that they represent a physiological step in the organization of alpha-Smooth-Muscle Actin in stress fibers. Fluorescence-recovery-after-photobleaching experiments suggest that the fusion peptide reduces the dynamics of alpha-Smooth-Muscle Actin and its incorporation in stress fibers. Here, we propose a new mechanism of how alpha-Smooth-Muscle Actin is incorporated in stress fibers involving the sequence Ac-EEED.
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The N-Terminal Ac-EEED Sequence Plays a Role in α-Smooth Muscle Actin Incorporation into Stress Fibers
Wound Repair and Regeneration, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:The main differences between the six known Actin isoforms are located in their amino terminus, suggesting a crucial importance for this region in terms of Actin isoform function and organization. We have recently supported this assumption by demonstrating that the α-Smooth Muscle Actin N-terminal sequence AcEEED introduced in myofibroblasts as a cell-penetrating fusion peptide causes: (i) the loss of α-Smooth Muscle Actin staining in stress fibers; and (ii) a decrease in cell contractility both in vitro and in vivo. Here we have further investigated the function of this sequence on stress fiber organization in living fibroblastic cells, using enhanced green fluorescent protein (EFGP)-tagged α-Smooth Muscle Actin. Approximately 30 minutes after application, the fusion peptide provokes gradual disappearance of α-Smooth Muscle Actin-EGFP fluorescence in stress fibers correlating temporally with the formation of rod-like structures of 2–20 μm length in approximately 60% of cells. Characterization of the α-Smooth Muscle Actin-containing rod-like structures shows that they additionally stain for β- and γ-cytoplasmic Actins, gelsolin and cofilin; in contrast, other major Actin-binding proteins, such as α-Actinin are absent from these structures. Interestingly rod-like structures are visible at submembranous cytoplasmic portion of normal cells during initial phases of spreading, suggesting that they represent a physiological step in α-Smooth Muscle Actin organization before incorporation in stress fibers. Fluorescence recovery after photobleaching experiments suggest that the fusion peptide reduces α-Smooth Muscle Actin dynamics and incorporation in stress fibers, rather than releasing it from stress fibers.
Sophie Clement - One of the best experts on this subject based on the ideXlab platform.
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Expression and function of alpha-Smooth Muscle Actin during embryonic-stem-cell-derived cardiomyocyte differentiation.
Journal of Cell Science, 2007Co-Authors: Sophie Clement, Christine Chaponnier, Michael Stouffs, Esther Bettiol, Sandy Kampf, Karl-heinz Krause, Marisa JaconiAbstract:Three alpha-Muscle Actin isoforms are sequentially expressed during in vivo cardiac development. alpha-Smooth Muscle Actin is first and transiently expressed, followed by alpha-skeletal and finally alpha-cardiac Actin. The significance of these transitions in Actin gene expression during myogenesis remains to be determined. To understand whether Actin isoforms have specific functions during cardiac development and cardiomyocyte contractility, we have hampered alpha-Smooth Muscle and alpha-skeletal Actin expression and organization during embryonic stem cell differentiation towards cardiomyocyte. We show that the sequence of Actin isoform expression displays similar pattern in the in vitro model and in mouse heart embryogenesis. Treatment with an interfering fusion peptide containing the N-terminal sequence of alpha-Smooth Muscle Actin during a time window preceding spontaneous beating, prevents proper cardiac sarcomyogenesis, whereas alpha-skeletal Actin-fusion peptide has no effect. Knockdown of alpha-Smooth Muscle Actin in embryonic stem cells using RNA interference also affects cardiac differentiation. The application of both fusion peptides on beating embryoid bodies impairs frequency. These results suggest specific functional activities for Actin isoforms in cardiogenesis and cardiomyocyte contractility.
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the n terminal ac eeed sequence plays a role in alpha Smooth Muscle Actin incorporation into stress fibers
Journal of Cell Science, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:We have previously shown that the N-terminal sequence AcEEED of alpha-Smooth-Muscle Actin causes the loss of alpha-Smooth-Muscle Actin from stress fibers and a decrease in cell contractility when introduced in myofibroblasts as a cell-penetrating fusion peptide. Here, we have investigated the function of this sequence on stress fiber organization in living cells, using enhanced green fluorescent protein (EGFP)-tagged alpha-Smooth-Muscle Actin. The fusion peptide provokes the gradual disappearance of EGFP fluorescence of alpha-Smooth-Muscle Actin from stress fibers and the formation of hitherto unknown rod-like structures. In addition to alpha-Smooth-Muscle Actin, these structures contain cytoplasmic Actins, gelsolin and cofilin but not other major Actin-binding proteins. These rod-like structures are also visible in wild-type fibroblasts during normal cell spreading, suggesting that they represent a physiological step in the organization of alpha-Smooth-Muscle Actin in stress fibers. Fluorescence-recovery-after-photobleaching experiments suggest that the fusion peptide reduces the dynamics of alpha-Smooth-Muscle Actin and its incorporation in stress fibers. Here, we propose a new mechanism of how alpha-Smooth-Muscle Actin is incorporated in stress fibers involving the sequence Ac-EEED.
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The N-Terminal Ac-EEED Sequence Plays a Role in α-Smooth Muscle Actin Incorporation into Stress Fibers
Wound Repair and Regeneration, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:The main differences between the six known Actin isoforms are located in their amino terminus, suggesting a crucial importance for this region in terms of Actin isoform function and organization. We have recently supported this assumption by demonstrating that the α-Smooth Muscle Actin N-terminal sequence AcEEED introduced in myofibroblasts as a cell-penetrating fusion peptide causes: (i) the loss of α-Smooth Muscle Actin staining in stress fibers; and (ii) a decrease in cell contractility both in vitro and in vivo. Here we have further investigated the function of this sequence on stress fiber organization in living fibroblastic cells, using enhanced green fluorescent protein (EFGP)-tagged α-Smooth Muscle Actin. Approximately 30 minutes after application, the fusion peptide provokes gradual disappearance of α-Smooth Muscle Actin-EGFP fluorescence in stress fibers correlating temporally with the formation of rod-like structures of 2–20 μm length in approximately 60% of cells. Characterization of the α-Smooth Muscle Actin-containing rod-like structures shows that they additionally stain for β- and γ-cytoplasmic Actins, gelsolin and cofilin; in contrast, other major Actin-binding proteins, such as α-Actinin are absent from these structures. Interestingly rod-like structures are visible at submembranous cytoplasmic portion of normal cells during initial phases of spreading, suggesting that they represent a physiological step in α-Smooth Muscle Actin organization before incorporation in stress fibers. Fluorescence recovery after photobleaching experiments suggest that the fusion peptide reduces α-Smooth Muscle Actin dynamics and incorporation in stress fibers, rather than releasing it from stress fibers.
Giulio Gabbiani - One of the best experts on this subject based on the ideXlab platform.
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the n terminal ac eeed sequence plays a role in alpha Smooth Muscle Actin incorporation into stress fibers
Journal of Cell Science, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:We have previously shown that the N-terminal sequence AcEEED of alpha-Smooth-Muscle Actin causes the loss of alpha-Smooth-Muscle Actin from stress fibers and a decrease in cell contractility when introduced in myofibroblasts as a cell-penetrating fusion peptide. Here, we have investigated the function of this sequence on stress fiber organization in living cells, using enhanced green fluorescent protein (EGFP)-tagged alpha-Smooth-Muscle Actin. The fusion peptide provokes the gradual disappearance of EGFP fluorescence of alpha-Smooth-Muscle Actin from stress fibers and the formation of hitherto unknown rod-like structures. In addition to alpha-Smooth-Muscle Actin, these structures contain cytoplasmic Actins, gelsolin and cofilin but not other major Actin-binding proteins. These rod-like structures are also visible in wild-type fibroblasts during normal cell spreading, suggesting that they represent a physiological step in the organization of alpha-Smooth-Muscle Actin in stress fibers. Fluorescence-recovery-after-photobleaching experiments suggest that the fusion peptide reduces the dynamics of alpha-Smooth-Muscle Actin and its incorporation in stress fibers. Here, we propose a new mechanism of how alpha-Smooth-Muscle Actin is incorporated in stress fibers involving the sequence Ac-EEED.
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The N-Terminal Ac-EEED Sequence Plays a Role in α-Smooth Muscle Actin Incorporation into Stress Fibers
Wound Repair and Regeneration, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:The main differences between the six known Actin isoforms are located in their amino terminus, suggesting a crucial importance for this region in terms of Actin isoform function and organization. We have recently supported this assumption by demonstrating that the α-Smooth Muscle Actin N-terminal sequence AcEEED introduced in myofibroblasts as a cell-penetrating fusion peptide causes: (i) the loss of α-Smooth Muscle Actin staining in stress fibers; and (ii) a decrease in cell contractility both in vitro and in vivo. Here we have further investigated the function of this sequence on stress fiber organization in living fibroblastic cells, using enhanced green fluorescent protein (EFGP)-tagged α-Smooth Muscle Actin. Approximately 30 minutes after application, the fusion peptide provokes gradual disappearance of α-Smooth Muscle Actin-EGFP fluorescence in stress fibers correlating temporally with the formation of rod-like structures of 2–20 μm length in approximately 60% of cells. Characterization of the α-Smooth Muscle Actin-containing rod-like structures shows that they additionally stain for β- and γ-cytoplasmic Actins, gelsolin and cofilin; in contrast, other major Actin-binding proteins, such as α-Actinin are absent from these structures. Interestingly rod-like structures are visible at submembranous cytoplasmic portion of normal cells during initial phases of spreading, suggesting that they represent a physiological step in α-Smooth Muscle Actin organization before incorporation in stress fibers. Fluorescence recovery after photobleaching experiments suggest that the fusion peptide reduces α-Smooth Muscle Actin dynamics and incorporation in stress fibers, rather than releasing it from stress fibers.
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Regulation of alpha-Smooth Muscle Actin and CRBP-1 expression by retinoic acid and TGF-beta in cultured fibroblasts.
Journal of cellular physiology, 2001Co-Authors: Marie-luce Bochaton-piallat, Giulio Gabbiani, Robert B. Low, Daniele Andreutti, Pascal NeuvilleAbstract:We have reported that Cellular Retinol Binding Protein-1 (CRBP-1) is expressed de novo during skin wound healing by a proportion of fibroblastic cells which then differentiate into myofibroblasts and express alpha-Smooth Muscle Actin. In fibroblasts cultured from different tissues we have shown that alpha-Smooth Muscle Actin expression, mainly controlled by Transforming Growth Factor-beta (TGF-beta), is also regulated by retinoic acid and that CRBP-1, known to be a retinoic acid-responsive gene, is modulated by TGF-beta. The aim of the present study has been to investigate the relationships between retinoic acid and TGF-beta in regulating the expression of CRBP-1 and alpha-Smooth Muscle Actin in cultured rat subcutaneous tissue fibroblasts. We have observed that the TGF-beta-induced, but not the retinoic acid-induced, alpha-Smooth Muscle Actin expression is associated with a modulation of endogenous TGF-beta and TGF-beta receptors, suggesting that the action of retinoic acid on alpha-Smooth Muscle Actin expression is not mediated by TGF-beta. The expression of CRBP-1 is regulated at the transcriptional level by TGF-beta and retinoic acid but not synergistically, suggesting a possible common pathway. However, retinoic acid, but not TGF-beta, increases the transcription of a transiently transfected chimeric construct containing the retinoic acid response element of the CRBP-1 promoter, indicating that TGF-beta does not influence CRBP-1 through the retinoic acid pathway. Our results indicate that distinct pathways regulate the genes involved in the appearance and evolution of the myofibroblastic cells. The characterization of these pathways will be helpful for the design of drugs influencing wound healing.
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Effect of hyaluronic acid on migration, proliferation and alpha-Smooth Muscle Actin expression by cultured rat and human fibroblasts.
Journal of submicroscopic cytology and pathology, 1999Co-Authors: Andreutti D, Geinoz A, Giulio GabbianiAbstract:Abstract Hyaluronic acid represents a major constituent of the extracellular matrix and influences numerous cellular processes. We have studied the effect of this molecule on migration, proliferation and alpha-Smooth Muscle Actin expression by rat and human cultured fibroblasts. Depending on the tissue origin of the fibroblasts, hyaluronic acid induced, inhibited or did not affect fibroblast migration, whereas proliferation was never affected. Alpha-Smooth Muscle Actin expression was inhibited by hyaluronic acid in all types of human and rat fibroblasts studied, but the inhibition was stronger and dose dependent for subcutaneous fibroblasts and for those recovered from Dupuytren's nodules. This property of inhibiting alpha-Smooth Muscle Actin expression makes hyaluronic acid a good candidate to exert antifibrotic activity.
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heparin induces alpha Smooth Muscle Actin expression in cultured fibroblasts and in granulation tissue myofibroblasts
Laboratory Investigation, 1992Co-Authors: Alexis Desmouliere, G Grau, Laura Rubbiabrandt, Giulio GabbianiAbstract:BACKGROUND: Heparin increases alpha-Smooth Muscle Actin expression in Smooth Muscle cells in vivo and in vitro. It has been recently suggested that alpha-Smooth Muscle Actin expression in fibroblasts is a marker of myofibroblastic differentiation. We have examined the effect of heparin and of four nonanticoagulant heparin derivatives on alpha-Smooth Muscle Actin expression by fibroblasts in vitro and in vivo. EXPERIMENTAL DESIGN: For in vitro experiments, heparin was added for 7 days to different fibroblastic cultures. We studied cell proliferation and alpha-Smooth Muscle Actin protein and mRNA expression. For in vivo studies, osmotic minipumps filled with NaCl or tumor necrosis factor-alpha without or with nonanticoagulant heparin were implanted subcutaneously. After 14 days, newly accumulated connective tissues around the pumps were processed for immunofluorescence and electron microscopic and biochemical studies. RESULTS: In vitro, heparin inhibited proliferation and increased the expression of alpha-Smooth Muscle Actin protein and mRNA. Analysis of [3H]thymidine incorporation in synchronized cells suggested that heparin produces a selection of alpha-Smooth Muscle Actin expressing cells. In vivo, the local application of tumor necrosis factor-alpha resulted in formation of a typical granulation tissue: immunofluorescence showed that accumulated fibroblastic cells express alpha-Smooth Muscle Actin only in the presence of heparin derivatives. In tumor necrosis factor-alpha treated animals, electron microscopic examination established the presence of myofibroblasts, but alpha-Smooth Muscle Actin was expressed in microfilament bundles only in the presence of heparin derivatives. CONCLUSIONS: These results show that heparin and its nonanticoagulant derivatives influence the expression of alpha-Smooth Muscle Actin in fibroblastic cells both in vitro and in vivo and that this effect is probably related to the selection of a particular cell subpopulation. They suggest a possible role for heparin during the formation and evolution of granulation tissue.
Boris Hinz - One of the best experts on this subject based on the ideXlab platform.
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the n terminal ac eeed sequence plays a role in alpha Smooth Muscle Actin incorporation into stress fibers
Journal of Cell Science, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:We have previously shown that the N-terminal sequence AcEEED of alpha-Smooth-Muscle Actin causes the loss of alpha-Smooth-Muscle Actin from stress fibers and a decrease in cell contractility when introduced in myofibroblasts as a cell-penetrating fusion peptide. Here, we have investigated the function of this sequence on stress fiber organization in living cells, using enhanced green fluorescent protein (EGFP)-tagged alpha-Smooth-Muscle Actin. The fusion peptide provokes the gradual disappearance of EGFP fluorescence of alpha-Smooth-Muscle Actin from stress fibers and the formation of hitherto unknown rod-like structures. In addition to alpha-Smooth-Muscle Actin, these structures contain cytoplasmic Actins, gelsolin and cofilin but not other major Actin-binding proteins. These rod-like structures are also visible in wild-type fibroblasts during normal cell spreading, suggesting that they represent a physiological step in the organization of alpha-Smooth-Muscle Actin in stress fibers. Fluorescence-recovery-after-photobleaching experiments suggest that the fusion peptide reduces the dynamics of alpha-Smooth-Muscle Actin and its incorporation in stress fibers. Here, we propose a new mechanism of how alpha-Smooth-Muscle Actin is incorporated in stress fibers involving the sequence Ac-EEED.
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The N-Terminal Ac-EEED Sequence Plays a Role in α-Smooth Muscle Actin Incorporation into Stress Fibers
Wound Repair and Regeneration, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:The main differences between the six known Actin isoforms are located in their amino terminus, suggesting a crucial importance for this region in terms of Actin isoform function and organization. We have recently supported this assumption by demonstrating that the α-Smooth Muscle Actin N-terminal sequence AcEEED introduced in myofibroblasts as a cell-penetrating fusion peptide causes: (i) the loss of α-Smooth Muscle Actin staining in stress fibers; and (ii) a decrease in cell contractility both in vitro and in vivo. Here we have further investigated the function of this sequence on stress fiber organization in living fibroblastic cells, using enhanced green fluorescent protein (EFGP)-tagged α-Smooth Muscle Actin. Approximately 30 minutes after application, the fusion peptide provokes gradual disappearance of α-Smooth Muscle Actin-EGFP fluorescence in stress fibers correlating temporally with the formation of rod-like structures of 2–20 μm length in approximately 60% of cells. Characterization of the α-Smooth Muscle Actin-containing rod-like structures shows that they additionally stain for β- and γ-cytoplasmic Actins, gelsolin and cofilin; in contrast, other major Actin-binding proteins, such as α-Actinin are absent from these structures. Interestingly rod-like structures are visible at submembranous cytoplasmic portion of normal cells during initial phases of spreading, suggesting that they represent a physiological step in α-Smooth Muscle Actin organization before incorporation in stress fibers. Fluorescence recovery after photobleaching experiments suggest that the fusion peptide reduces α-Smooth Muscle Actin dynamics and incorporation in stress fibers, rather than releasing it from stress fibers.
V B Dugina - One of the best experts on this subject based on the ideXlab platform.
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the n terminal ac eeed sequence plays a role in alpha Smooth Muscle Actin incorporation into stress fibers
Journal of Cell Science, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:We have previously shown that the N-terminal sequence AcEEED of alpha-Smooth-Muscle Actin causes the loss of alpha-Smooth-Muscle Actin from stress fibers and a decrease in cell contractility when introduced in myofibroblasts as a cell-penetrating fusion peptide. Here, we have investigated the function of this sequence on stress fiber organization in living cells, using enhanced green fluorescent protein (EGFP)-tagged alpha-Smooth-Muscle Actin. The fusion peptide provokes the gradual disappearance of EGFP fluorescence of alpha-Smooth-Muscle Actin from stress fibers and the formation of hitherto unknown rod-like structures. In addition to alpha-Smooth-Muscle Actin, these structures contain cytoplasmic Actins, gelsolin and cofilin but not other major Actin-binding proteins. These rod-like structures are also visible in wild-type fibroblasts during normal cell spreading, suggesting that they represent a physiological step in the organization of alpha-Smooth-Muscle Actin in stress fibers. Fluorescence-recovery-after-photobleaching experiments suggest that the fusion peptide reduces the dynamics of alpha-Smooth-Muscle Actin and its incorporation in stress fibers. Here, we propose a new mechanism of how alpha-Smooth-Muscle Actin is incorporated in stress fibers involving the sequence Ac-EEED.
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The N-Terminal Ac-EEED Sequence Plays a Role in α-Smooth Muscle Actin Incorporation into Stress Fibers
Wound Repair and Regeneration, 2005Co-Authors: Sophie Clement, V B Dugina, Boris Hinz, Giulio Gabbiani, Christine ChaponnierAbstract:The main differences between the six known Actin isoforms are located in their amino terminus, suggesting a crucial importance for this region in terms of Actin isoform function and organization. We have recently supported this assumption by demonstrating that the α-Smooth Muscle Actin N-terminal sequence AcEEED introduced in myofibroblasts as a cell-penetrating fusion peptide causes: (i) the loss of α-Smooth Muscle Actin staining in stress fibers; and (ii) a decrease in cell contractility both in vitro and in vivo. Here we have further investigated the function of this sequence on stress fiber organization in living fibroblastic cells, using enhanced green fluorescent protein (EFGP)-tagged α-Smooth Muscle Actin. Approximately 30 minutes after application, the fusion peptide provokes gradual disappearance of α-Smooth Muscle Actin-EGFP fluorescence in stress fibers correlating temporally with the formation of rod-like structures of 2–20 μm length in approximately 60% of cells. Characterization of the α-Smooth Muscle Actin-containing rod-like structures shows that they additionally stain for β- and γ-cytoplasmic Actins, gelsolin and cofilin; in contrast, other major Actin-binding proteins, such as α-Actinin are absent from these structures. Interestingly rod-like structures are visible at submembranous cytoplasmic portion of normal cells during initial phases of spreading, suggesting that they represent a physiological step in α-Smooth Muscle Actin organization before incorporation in stress fibers. Fluorescence recovery after photobleaching experiments suggest that the fusion peptide reduces α-Smooth Muscle Actin dynamics and incorporation in stress fibers, rather than releasing it from stress fibers.