共查询到20条相似文献,搜索用时 31 毫秒
1.
Aims
Deleted in liver cancer 1 (DLC1), a member of RhoGTPase activating protein (GAP) family, is known to have suppressive activities in tumorigenicity and cancer metastasis. However, the underlying molecular mechanisms of how DLC1 suppresses cell motility have not been fully elucidated. Rho-kinase (ROCK) is an immediate down-stream effector of RhoA in mediating cellular cytoskeletal events and cell motility. In the present study, we aimed to investigate the effects of DLC1 on Rho/ROCK signaling pathway in hepatocellular carcinoma (HCC).Methodology/Principal Findings
We demonstrated that DLC1 negatively regulated ROCK-dependent actomyosin contractility. From immumofluorescence study, we found that ectopic expression of DLC1 abrogated Rho/ROCK-mediated cytoskeletal reorganization including formation of stress fibers and focal adhesions. It also downregulated cortical phosphorylation of myosin light chain 2 (MLC2). These inhibitory events by DLC1 were RhoGAP-dependent, as RhoGAP-deficient mutant of DLC1 (DLC1 K714E) abolished these inhibitory events. In addition, from western study, DLC1 inhibited ROCK-related myosin light chain phosphatase targeting unit 1 (MYPT1) phosphorylation at Threonine 853. By examining cell morphology under microscope, we found that ectopic expression of dominant-active ROCK released cells from DLC1-induced cytoskeletal collapse and cell shrinkage.Conclusion
Our data suggest that DLC1 negatively regulates Rho/ROCK/MLC2. This implicates a ROCK-mediated pathway of DLC1 in suppressing metastasis of HCC cells and enriches our understanding in the molecular mechanisms involved in the progression of hepatocellular carcinoma. 相似文献2.
Stull James T. Tansey Malú G. Tang Da-Chun Word R. Ann Kamm Kristine E. 《Molecular and cellular biochemistry》1993,127(1):229-237
Phosphorylation of the regulatory light chain of myosin by the Ca2+/calmodulin-dependent myosin light chain kinase plays an important role in smooth muscle contraction, nonmuscle cell shape changes, platelet contraction, secretion, and other cellular processes. Smooth muscle myosin light chain kinase is also phosphorylated, and recent results from experiments designed to satisfy the criteria of Krebs and Beavo for establishing the physiological significance of enzyme phosphorylation have provided insights into the cellular regulation and function of this phosphorylation in smooth muscle. The multifunctional Ca2+/calmodulin-dependent protein kinase II phosphorylates myosin light chain kinase at a regulatory site near the calmodulin-binding domain. This phosphorylation increases the concentration of Ca2+/calmodulin required for activation and hence increases the Ca2+ concentrations required for myosin light chain kinase activity in cells. However, the concentration of cytosolic Ca2+ required to effect myosin light chain kinase phosphorylation is greater than that required for myosin light chain phosphorylation. Phosphorylation of myosin light chain kinase is only one of a number of mechanisms used by the cell to down regulate the Ca2+ signal in smooth muscle. Since both smooth and nonmuscle cells express the same form of myosin light chain kinase, this phosphorylation may play a regulatory role in cellular processes that are dependent on myosin light chain phosphorylation. 相似文献
3.
Objective
Melatonin, an indolamine produced and secreted predominately by the pineal gland, exhibits a variety of physiological functions, possesses antioxidant and antitumor properties. But, the mechanisms for the anti-cancer effects are unknown. The present study explored the effects of melatonin on the migration of human lung adenocarcinoma A549 cells and its mechanism.Methods
MTT assay was employed to measure the viability of A549 cells treated with different concentrations of melatonin. The effect of melatonin on the migration of A549 cells was analyzed by wound healing assay. Occludin location was observed by immunofluorescence. The expression of occludin, osteopontin (OPN), myosin light chain kinase (MLCK) and phosphorylation of myosin light chain (MLC), JNK were detected by western blots.Results
After A549 cells were treated with melatonin, the viability and migration of the cells were inhibited significantly. The relative migration rate of A549 cells treated with melatonin was only about 20% at 24 h. The expression level of OPN, MLCK and phosphorylation of MLC of A549 cells were reduced, while the expression of occludin was conversely elevated, and occludin located on the cell surface was obviously increased. The phosphorylation status of JNK in A549 cells was also reduced when cells were treated by melatonin.Conclusions
Melatonin significantly inhibits the migration of A549 cells, and this may be associated with the down-regulation of the expression of OPN, MLCK, phosphorylation of MLC, and up-regulation of the expression of occludin involving JNK/MAPK pathway. 相似文献4.
Kolega J 《Journal of cellular biochemistry》1999,75(4):629-639
Assembly and motor activity of non-muscle myosin II can be regulated by phosphorylation. Because myosin II-containing structures undergo continuous assembly, disassembly, and remodeling in living cells, especially during cell migration, myosin II should undergo frequent phosphorylation and dephosphorylation. This study examines the turnover of phosphate on myosin II in stationary and migrating endothelial cells. Cultured bovine aortic endothelial cells were metabolically labeled with (32)P-phosphate, and the incorporation of phosphate into myosin II was assessed by quantitative phosphor imaging of electrophoretic gels of myosin II immunoadsorbed from cell lysates. Likewise, phosphate turnover was measured upon chasing the (32)P with unlabeled phosphate. Phosphate incorporated very slowly into heavy chains, taking >8 h to plateau, and turned over at =12.7% per hour. Regulatory light chains became completely labeled in =4 h, and turnover occurred at two rates: 49% turned over at 20% per hour, the remainder at 67% per hour. Peptide mapping showed light chain phosphorylation at serine 19 and threonine 18, but phosphate turnover was the same in mono- and diphosphorylated lights chains, indicating that rates are not different at the two sites. When cells were stimulated to migrate by wounding a confluent monolayer, the rate of light chain dephosphorylation increased and the rate of phosphate incorporation decreased causing a net 10% dephosphorylation of light chains. This process persisted during migration and returned to baseline when the wound was closed. There was no effect on heavy chain phosphates. Light chain dephosphorylation may facilitate migration by mobilizing myosin II during cytoskeletal remodeling. 相似文献
5.
Many non-muscle cells including chromaffin cells contain actin and myosin. The 20,000 dalton light chain subunits of myosin can be phosphorylated by a Ca2+/calmodulin-dependent enzyme, myosin light chain kinase. In tissues other than striated muscle, light chain phosphorylation is required for actin-induced myosin ATPase activity. The possibility that actin and myosin are involved in catecholamine secretion was investigated by determining whether increased phosphorylation in the presence of [-32P]ATP of myosin light chain by myosin light chain kinase enhances secretion from digitonin-treated chromaffin cells. In the absence of exogenous myosin light chain kinase, 1 M Ca2+ caused a 30–40% enhancement of the phosphorylation of a 20 kDa protein. This protein was identified on 2-dimensional gels as myosin light chain by its comigration with purified myosin light chain. Purified myosin light chain kinase (400 g/ml) in the presence of calmodulin (10 M) caused little or no enhancement of myosin light chain phosphorylation in the absence of Ca2+ in digitonin-treated cells. In the presence of 1 M Ca2+, myosin light chain kinase (400 g/ml) caused an approximately two-fold increase in myosin light chain phosphorylation in digitonin-treated cells in 5 min. The phosphorylation required permeabilization of the cells by digitonin and occurred within the cells rather than in the medium. Myosin light chain kinase-induced phosphorylation of myosin light chain was maximal at 1 M. Ca2+. Under identical conditions to those of the phosphorylation experiments, secretion was unaltered by myosin light chain kinase. The experiments indicate that the phosphorylation of myosin light chain by myosin light chain kinase is not a limiting factor in secretion in digitonin-treated chromaffin cells and suggest that the activation of myosin is not directly involved in secretion from the cells. The experiments also demonstrate the feasibility of investigation of effects of exogenously added proteins on secretion in digitonin-treated cells.Abbreviations EGTA
ethyleneglycol-bis-(-aminoethyl ether)-N,N,N,N-tetraacetic acid
- HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- KGEPM
solution containing potassium glutamate, EGTA, PIPES and MgCl2
- NE
norepinephrine
- PIPES
piperazine-N,-N-bis-(2-ethanesulfonic acid)
- PSS
physiological salt solution 相似文献
6.
Purpose
The trabecular meshwork (TM) cell-matrix interactions and factors that influence Rho signaling in TM cells are thought to play a pivotal role in the regulation of aqueous outflow. The current study was designed to evaluate the role of a carbohydrate-binding protein, galectin-8 (Gal8), in TM cell adhesion and Rho signaling.Methods
Normal human TM cells were assayed for Gal8 expression by immunohistochemistry and Western blot analysis. To assess the role of Gal8 in TM cell adhesion and Rho signaling, the cell adhesion and spreading assays were performed on Gal8-coated culture plates in the presence and the absence of anti-β1 integrin antibody and Rho and Rho-kinase inhibitors. In addition, the effect of Gal8-mediated cell-matrix interactions on TM cell cytoskeleton arrangement and myosin light chain 2 (MLC2) phosphorylation was examined.Principal Findings
We demonstrate here that Gal8 is expressed in the TM and a function-blocking anti-β1 integrin antibody inhibits the adhesion and spreading of TM cells to Gal8-coated wells. Cell spreading on Gal8 substratum was associated with the accumulation of phosphorylated myosin light chain and the formation of stress fibers that was inhibited by the Rho inhibitor, C3 transferase, as well as by the Rho-kinase inhibitor, Y27632.Conclusions/Significance
The above findings present a novel function for Gal8 in activating Rho signaling in TM cells. This function may allow Gal8 to participate in the regulation of aqueous outflow. 相似文献7.
Jean-Charles Gabillard Cécile Rallière Nathalie Sabin Pierre-Yves Rescan 《BMC biotechnology》2010,10(1):39
Background
Fish skeletal muscle growth involves the activation of a resident myogenic stem cell population, referred to as satellite cells, that can fuse with pre-existing muscle fibers or among themselves to generate a new fiber. In order to monitor the regulation of myogenic cell differentiation and fusion by various extrinsic factors, we generated transgenic trout (Oncorhynchus mykiss) carrying a construct containing the green fluorescent protein reporter gene driven by a fast myosin light chain 2 (MlC2f) promoter, and cultivated genetically modified myogenic cells derived from these fish. 相似文献8.
Background
Previously it has been shown that insulin-mediated tyrosine phosphorylation of myosin heavy chain is concomitant with enhanced association of C-terminal SRC kinase during skeletal muscle differentiation. We sought to identify putative site(s) for this phosphorylation event. 相似文献9.
Vascular smooth muscle cell contraction and relaxation are directly related to the phosphorylation state of the regulatory myosin light chain. Myosin light chains are dephosphorylated by myosin phosphatase, leading to vascular smooth muscle relaxation. Myosin phosphatase is localized not only at actin-myosin stress fibers where it dephosphorylates myosin light chains, but also in the cytoplasm and at the cell membrane. The mechanisms by which myosin phosphatase is targeted to these loci are incompletely understood. We recently identified myosin phosphatase-Rho interacting protein as a member of the myosin phosphatase complex that directly binds both the myosin binding subunit of myosin phosphatase and RhoA and is localized to actin-myosin stress fibers. We hypothesized that myosin phosphatase-Rho interacting protein targets myosin phosphatase to the contractile apparatus to dephosphorylate myosin light chains. We used RNA interference to silence the expression of myosin phosphatase-Rho interacting protein in human vascular smooth muscle cells. Myosin phosphatase-Rho interacting protein silencing reduced the localization of the myosin binding subunit to stress fibers. This reduction in stress fiber myosin phosphatase-Rho interacting protein and myosin binding subunit increased basal and lysophosphatidic acid-stimulated myosin light chain phosphorylation. Neither cellular myosin phosphatase, myosin light chain kinase, nor RhoA activities were changed by myosin phosphatase-Rho interacting protein silencing. Furthermore, myosin phosphatase-Rho interacting protein silencing resulted in marked phenotypic changes in vascular smooth muscle cells, including increased numbers of stress fibers, increased cell area, and reduced stress fiber inhibition in response to a Rho-kinase inhibitor. These data support the importance of myosin phosphatase-Rho interacting protein-dependent targeting of myosin phosphatase to stress fibers for regulating myosin light chain phosphorylation state and morphology in human vascular smooth muscle cells. 相似文献
10.
Background
Anti-angiogenic activity is considered to play a key role in the statin-induced anti-tumor effects. We aimed to identify new targets underlying this pleiotropic effect of lovastatin.Methodology/Principal Findings
We investigated the inhibitory effects of lovastatin on endothelial cell biology and angiogenesis in vitro. Lovastatin at high doses inhibited endothelial cell migration and tube formation. Using two-dimensional gel electrophoresis followed by mass spectrometry, we identified the up-regulation of the actin-binding protein transgelin 2 in endothelial cells following treatment with lovastatin. Changes in transgelin 2 levels were confirmed by Western blot and confocal microscopy. We further demonstrated that the Rho signaling inactivation and actin depolymerization contributed to the up-regulation of transgelin 2. The knockdown of transgelin 2 by siRNA dramatically enhanced endothelial migration and tube formation, and meanwhile attenuated the inhibitory effects of lovastatin on cell motility. Moreover, the lovastatin-induced inhibition of myosin light chain phosphorylation was also reversed by transgelin 2 knockdown. The activation of Rho GTPase in the absence of transgelin 2 may represent a mechanism underlying the regulation of phosphorylated myosin light chain by transgelin 2.Conclusions/Significance
These results strongly imply a novel role for transgelin 2 in the angiostatic activities of lovastatin. 相似文献11.
Background
Nitroglycerin can induce relaxation of swine carotid artery without sustained reductions in [Ca2+]i or myosin regulatory light chain (MRLC) phosphorylation. This has been termed force suppression and been found to correlate with ser16-phosphorylation of heat shock protein 20 (HSP20). We tested for the existence of this mechanism in a smooth muscle that is not responsive to nitric oxide. 相似文献12.
Differential localization in cells of myosin II heavy chain kinases during cytokinesis and polarized migration 总被引:1,自引:0,他引:1
Wenchuan Liang Lucila S Licate Hans M Warrick James A Spudich Thomas T Egelhoff 《BMC cell biology》2002,3(1):19-16
Background
Cortical myosin-II filaments in Dictyostelium discoideum display enrichment in the posterior of the cell during cell migration and in the cleavage furrow during cytokinesis. Filament assembly in turn is regulated by phosphorylation in the tail region of the myosin heavy chain (MHC). Early studies have revealed one enzyme, MHCK-A, which participates in filament assembly control, and two other structurally related enzymes, MHCK-B and -C. In this report we evaluate the biochemical properties of MHCK-C, and using fluorescence microscopy in living cells we examine the localization of GFP-labeled MHCK-A, -B, and -C in relation to GFP-myosin-II localization. 相似文献13.
Peter C. Newell 《Bioscience reports》1995,15(6):445-462
This review is concerned with the roles of cyclic GMP and Ca2+ ions in signal transduction for chemotaxis ofDictyostelium. These molecules are involved in signalling between the cell surface cyclic AMP receptors and cytoskeletal myosin II involved in chemotactic cell movement. Evidence is presented for uptake and/or eflux of Ca2+ being regulated by cyclic GMP. The link between Ca2+, cyclic GMP and chemotactic cell movement has been explored using streamer F mutants whose primary defect is in the structural gene for the cyclic GMP-specific phosphodiesterase. This mutation causes the mutants to produce an abnormally prolonged peak of cyclic GMP accumulation in response to stimulation with the chemoattractant cyclic AMP. The production and relay of cyclic AMP signals is normal in these mutants, but certain events associated with movement are (like the cyclic GMP response) abnormally prolonged in the mutants. These events include Ca2+ uptake, myosin II association with the cytoskeleton and regulation of both myosin heavy and light chain phosphorylation. These changes can be correlated with changes in the shape of the amoebae after chemotactic stimulation. Other mutants in which the accumulation of cyclic GMP in response to cyclic AMP stimulation was absent produced no myosin II responses.A model is described in which cyclic GMP (directly or indirectly via Ca2+) regulates accumulation of myosin II on the cytoskeleton by regulating phosphorylation of the myosin heavy and light chain kinases. 相似文献
14.
Xinwei Mu Chen Pan Shuyun Zheng Yasir Alhamdi Bingwei Sun Qiankun Shi Xiang Wang Zhiwei Sun Chenghock Toh Guozheng Wang 《PloS one》2014,9(8)
Objective
To investigate the protective effects and mechanisms of carbon monoxide-releasing molecule-2 (CORM-2) on barrier function of intestinal epithelial cells.Materials and Methods
After pre-incubation with CORM-2 for 1 hour, cultured intestinal epithelial IEC-6 cells were stimulated with 50 µg/ml lipopolysaccharides (LPS). Cytokines levels in culture medium were detected using ELISA kits. Trans-epithelial electrical resistance (TER) of IEC-6 cell monolayers in Transwells were measured with a Millipore electric resistance system (ERS-2; Millipore) and calculated as Ω/cm2 at different time points after LPS treatment. The permeability changes were also measured using FITC-dextran. The levels of tight junction (TJ) proteins (occludin and ZO-1) and myosin light chain (MLC) phosphorylation were detected using Western blotting with specific antibodies. The subsequent structural changes of TJ were visualized using transmission electron microscopy (TEM).Results
CORM-2 significantly reduced LPS-induced secretion of TNF-α and IL-1β. The LPS-induced decrease of TER and increase of permeability to FITC-dextran were inhibited by CORM-2 in a concentration dependent manner (P<0.05). LPS-induced reduction of tight junction proteins and increase of MLC phosphorylation were also attenuated. In LPS-treated cells, TEM showed diminished electron-dense material and interruption of TJ and desmosomes between the apical lateral margins of adjoining cells, which were prevented by CORM-2 treatment.Conclusions
The present study demonstrates that CORM-2, as a novel CO-releasing molecule, has ability to protect the barrier function of LPS-stimulated intestinal epithelial cells. Inhibition of inflammatory cytokines release, restoration of TJ proteins and suppression of MLC phosphorylation are among the protective effects of CORM-2. 相似文献15.
16.
Rho-kinase inhibitor retards migration and in vivo dissemination of human prostate cancer cells 总被引:20,自引:0,他引:20
Somlyo AV Bradshaw D Ramos S Murphy C Myers CE Somlyo AP 《Biochemical and biophysical research communications》2000,269(3):652-659
The Rho-kinase inhibitor, Y-27632, inhibited in vitro chemotactic migration to bone marrow fibroblast conditioned media and metastatic growth in immune-compromised mice of highly invasive human prostatic cancer (PC3) cells. Y-27632 also reduced myosin light chain phosphorylation and markedly altered the morphology of cells that developed numerous processes containing microtubules. A strikingly different, rounded phenotype was induced by an inhibitor of myosin light chain kinase, ML9. The M(110-130) subunit of the myosin phosphatase that is regulated by Rho-kinase was present in PC3 cells that contained significantly more RhoA than the less invasive, LNCaP cells. Y-27632 also inhibited angiogenesis as measured by endothelial cell tube formation on Matrigel. We conclude that invasiveness of human prostate cancer is facilitated by the Rho/Rho-kinase pathway, and exploration of selective Rho-kinase inhibitors for limiting invasive progress of prostate cancer is warranted. 相似文献
17.
Serine/threonine p21-activated kinase is an effector of Rac with a key role in the regulation of cytoskeletal organization. Non-muscle myosin II is a molecular motor, which is an important component of the cytoskeleton. Non-muscle myosin II-B plays a major role in cell motility and chemotaxis. We investigated the role of Rac and p21-activated kinase 1 (PAK1) in the regulation of myosin II-B in prostate cancer cells in response to epidermal growth factor (EGF) stimulation. We found that both Rac and PAK1 affect EGF-dependent non-muscle heavy chain II-B localization and cell morphology. We further found that a dominant negative mutant of PAK1 significantly inhibits EGF-dependent myosin II-B heavy chains phosphorylation and filament disassembly. Furthermore, cells expressing the dominant negative mutant exhibited an increase in EGF-dependent myosin light chain phosphorylation and diminished chemotaxis towards EGF. To our knowledge this is the first report exploring the role of PAK1 in the regulation of both non-muscle myosin II-B heavy chains and light chains. Furthermore, the data presented here suggest that PAK1 plays a crucial role in the regulation of cell morphology and chemotaxis by regulating the phosphorylation and cellular localization of myosin II-B. 相似文献
18.
Background
The ‘phosphate-binding tag’ (phos-tag) reagent enables separation of phospho-proteins during SDS-PAGE by impeding migration proportional to their phosphorylation stoichiometry. Western blotting can then be used to detect and quantify the bands corresponding to the phospho-states of a target protein. We present a method for quantification of data regarding phospho-states derived from phos-tag SDS-PAGE. The method incorporates corrections for lane-to-lane loading variability and for the effects of drug vehicles thus enabling the comparison of multiple treatments by using the untreated cellular set-point as a reference. This method is exemplified by quantifying the phosphorylation of myosin regulatory light chain (RLC) in cultured human uterine myocytes.Methodology/Principal Findings
We have evaluated and validated the concept that, when using an antibody (Ab) against the total-protein, the sum of all phosphorylation states in a single lane represents a ‘closed system’ since all possible phospho-states and phosphoisotypes are detected. Using this approach, we demonstrate that oxytocin (OT) and calpeptin (Calp) induce RLC kinase (MLCK)- and rho-kinase (ROK)-dependent enhancements in phosphorylation of RLC at T18 and S19. Treatment of myocytes with a phorbol ester (PMA) induced phosphorylation of S1-RLC, which caused a mobility shift in the phos-tag matrices distinct from phosphorylation at S19.Conclusion/Significance
We have presented a method for analysis of phospho-state data that facilitates quantitative comparison to a reference control without the use of a traditional ‘loading’ or ‘reference’ standard. This analysis is useful for assessing effects of putative agonists and antagonists where all phospho-states are represented in control and experimental samples. We also demonstrated that phosphorylation of RLC at S1 is inducible in intact uterine myocytes, though the signal in the resting samples was not sufficiently abundant to allow quantification by the approach used here. 相似文献19.
Emmert DA Fee JA Goeckeler ZM Grojean JM Wakatsuki T Elson EL Herring BP Gallagher PJ Wysolmerski RB 《American journal of physiology. Cell physiology》2004,286(1):C8-21
Thus far, determining the relative contribution of Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) and Ca2+-independent Rho-kinase pathways to myosin II activation and contraction has been difficult. In this study, we characterize the role of Rho-kinase in a rat embryo fibroblast cell line (REF-52), which contains no detectable MLCK. No endogenous MLCK could be detected in REF-52 cells by either Western or Northern blot analysis. In the presence or absence of Ca2+, thrombin or lysophosphatidic acid (LPA) increased RhoA activity and Rhokinase activity, correlating with isometric tension development and myosin II regulatory light chain (RLC) phosphorylation. Resting tension is associated with a basal phosphorylation of 0.31 ± 0.02 mol PO4/mol RLC, whereas upon LPA or thrombin treatment myosin II RLC phosphorylation increases to 1.08 ± 0.05 and 0.82 ± 0.05 mol PO4/mol RLC, respectively, within 2.5 min. Ca2+ chelation has minimal effect on the kinetics and magnitude of isometric tension development and RLC phosphorylation. Treatment of REF-52 cells with the Rho-kinase-specific inhibitor Y-27632 abolished thrombin- and LPA-stimulated contraction and RLC phosphorylation. These results suggest that Rho-kinase is sufficient to activate myosin II motor activity and contraction in REF-52 cells. myosin light chain kinase; RhoA; myosin II regulatory light chain phosphorylation 相似文献
20.
Goeckeler ZM Bridgman PC Wysolmerski RB 《American journal of physiology. Cell physiology》2008,295(4):C994-1006
Cultured confluent endothelial cells exhibit stable basal isometric tone associated with constitutive myosin II regulatory light chain (RLC) phosphorylation. Thrombin treatment causes a rapid increase in isometric tension concomitant with myosin II RLC phosphorylation, actin polymerization, and stress fiber reorganization while inhibitors of myosin light chain kinase (MLCK) and Rho-kinase prevent these responses. These findings suggest a central role for myosin II in the regulation of endothelial cell tension. The present studies examine the effects of blebbistatin, a specific inhibitor of myosin II activity, on basal tone and thrombin-induced tension development. Although blebbistatin treatment abolished basal tension, this was accompanied by an increase in myosin II RLC phosphorylation. The increase in RLC phosphorylation was Ca2+ dependent and mediated by MLCK. Similarly, blebbistatin inhibited thrombin-induced tension without interfering with the increase in RLC phosphorylation or in F-actin polymerization. Blebbistatin did prevent myosin II filament incorporation and association with polymerizing or reorganized actin filaments leading to the disappearance of stress fibers. Thus the inhibitory effects of blebbistatin on basal tone and induced tension are consistent with a requirement for myosin II activity to maintain stress fiber integrity. actin; blebbistatin; isometric tension; myosin light chain kinase; regulatory light chain phosphorylation; focal adhesions 相似文献