scholarly journals Anillin Binds Nonmuscle Myosin II and Regulates the Contractile Ring

2005 ◽  
Vol 16 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Aaron F. Straight ◽  
Christine M. Field ◽  
Timothy J. Mitchison
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Cultured Cells ◽  
Contractile Activity ◽  
Myosin Ii ◽  
Human Cells ◽  
Myosin Light Chain Phosphorylation ◽  
Nonmuscle Myosin ◽  
Contractile Ring ◽  
Nonmuscle Myosin Ii

We demonstrate that the contractile ring protein anillin interacts directly with nonmuscle myosin II and that this interaction is regulated by myosin light chain phosphorylation. We show that despite their interaction, anillin and myosin II are independently targeted to the contractile ring. Depletion of anillin in Drosophila or human cultured cells results in cytokinesis failure. Human cells depleted for anillin fail to properly regulate contraction by myosin II late in cytokinesis and fail in abscission. We propose a role for anillin in spatially regulating the contractile activity of myosin II during cytokinesis.

scholarly journals Rap1 Activation in Collagen Phagocytosis Is Dependent on Nonmuscle Myosin II-A

2008 ◽  
Vol 19 (12) ◽  
pp. 5032-5046 ◽  
Author(s):  
Pamela D. Arora ◽  
Mary Anne Conti ◽  
Shoshana Ravid ◽  
David B. Sacks ◽  
Andras Kapus ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Cell Attachment ◽  
Myosin Ii ◽  
Myosin Light Chain Phosphorylation ◽  
Nonmuscle Myosin ◽  
Permeabilized Cells ◽  
Collagen Phagocytosis ◽  
Rap1 Activation

Rap1 enhances integrin-mediated adhesion but the link between Rap1 activation and integrin function in collagen phagocytosis is not defined. Mass spectrometry of Rap1 immunoprecipitates showed that the association of Rap1 with nonmuscle myosin heavy-chain II-A (NMHC II-A) was enhanced by cell attachment to collagen beads. Rap1 colocalized with NM II-A at collagen bead-binding sites. There was a transient increase in myosin light-chain phosphorylation after collagen-bead binding that was dependent on myosin light-chain kinase but not Rho kinase. Inhibition of myosin light-chain phosphorylation, but not myosin II-A motor activity inhibited collagen-bead binding and Rap activation. In vitro binding assays demonstrated binding of Rap1A to filamentous myosin rods, and in situ staining of permeabilized cells showed that NM II-A filaments colocalized with F-actin at collagen bead sites. Knockdown of NM II-A did not affect talin, actin, or β1-integrin targeting to collagen beads but targeting of Rap1 and vinculin to collagen was inhibited. Conversely, knockdown of Rap1 did not affect localization of NM II-A to beads. We conclude that MLC phosphorylation in response to initial collagen-bead binding promotes NM II-A filament assembly; binding of Rap1 to myosin filaments enables Rap1-dependent integrin activation and enhanced collagen phagocytosis.

Ca2+ Sensitivity of Smooth Muscle and Nonmuscle Myosin II: Modulated by G Proteins, Kinases, and Myosin Phosphatase

2003 ◽  
Vol 83 (4) ◽  
pp. 1325-1358 ◽  
Author(s):  
ANDREW P. SOMLYO ◽  
AVRIL V. SOMLYO
Keyword(s):  
Smooth Muscle ◽  
G Proteins ◽  
Cancer Progression ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Myosin Phosphatase ◽  
Lim Kinase ◽  
Nonmuscle Myosin Ii

Somlyo, Andrew P., and Avril V. Somlyo. Ca2+ Sensitivity of Smooth Muscle and Nonmuscle Myosin II: Modulated by G Proteins, Kinases, and Myosin Phosphatase. Physiol Rev 83: 1325-1358, 2003; 10.1152/physrev.00023.2003.— Ca2+ sensitivity of smooth muscle and nonmuscle myosin II reflects the ratio of activities of myosin light-chain kinase (MLCK) to myosin light-chain phosphatase (MLCP) and is a major, regulated determinant of numerous cellular processes. We conclude that the majority of phenotypes attributed to the monomeric G protein RhoA and mediated by its effector, Rho-kinase (ROK), reflect Ca2+ sensitization: inhibition of myosin II dephosphorylation in the presence of basal (Ca2+ dependent or independent) or increased MLCK activity. We outline the pathway from receptors through trimeric G proteins (Gαq, Gα12, Gα13) to activation, by guanine nucleotide exchange factors (GEFs), from GDP · RhoA · GDI to GTP · RhoA and hence to ROK through a mechanism involving association of GEF, RhoA, and ROK in multimolecular complexes at the lipid cell membrane. Specific domains of GEFs interact with trimeric G proteins, and some GEFs are activated by Tyr kinases whose inhibition can inhibit Rho signaling. Inhibition of MLCP, directly by ROK or by phosphorylation of the phosphatase inhibitor CPI-17, increases phosphorylation of the myosin II regulatory light chain and thus the activity of smooth muscle and nonmuscle actomyosin ATPase and motility. We summarize relevant effects of p21-activated kinase, LIM-kinase, and focal adhesion kinase. Mechanisms of Ca2+ desensitization are outlined with emphasis on the antagonism between cGMP-activated kinase and the RhoA/ROK pathway. We suggest that the RhoA/ROK pathway is constitutively active in a number of organs under physiological conditions; its aberrations play major roles in several disease states, particularly impacting on Ca2+ sensitization of smooth muscle in hypertension and possibly asthma and on cancer neoangiogenesis and cancer progression. It is a potentially important therapeutic target and a subject for translational research.

scholarly journals Myosin Motors and Not Actin Comets Are Mediators of the Actin-based Golgi-to-Endoplasmic Reticulum Protein Transport

2003 ◽  
Vol 14 (2) ◽  
pp. 445-459 ◽  
Author(s):  
Juan M. Durán ◽  
Ferran Valderrama ◽  
Susana Castel ◽  
Juana Magdalena ◽  
Mónica Tomás ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Light Chain ◽  
Shiga Toxin ◽  
Actin Filaments ◽  
Protein Transport ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii ◽  
Myosin Motors

We have previously reported that actin filaments are involved in protein transport from the Golgi complex to the endoplasmic reticulum. Herein, we examined whether myosin motors or actin comets mediate this transport. To address this issue we have used, on one hand, a combination of specific inhibitors such as 2,3-butanedione monoxime (BDM) and 1-[5-isoquinoline sulfonyl]-2-methyl piperazine (ML7), which inhibit myosin and the phosphorylation of myosin II by the myosin light chain kinase, respectively; and a mutant of the nonmuscle myosin II regulatory light chain, which cannot be phosphorylated (MRLC2AA). On the other hand, actin comet tails were induced by the overexpression of phosphatidylinositol phosphate 5-kinase. Cells treated with BDM/ML7 or those that express the MRLC2AA mutant revealed a significant reduction in the brefeldin A (BFA)-induced fusion of Golgi enzymes with the endoplasmic reticulum (ER). This delay was not caused by an alteration in the formation of the BFA-induced tubules from the Golgi complex. In addition, the Shiga toxin fragment B transport from the Golgi complex to the ER was also altered. This impairment in the retrograde protein transport was not due to depletion of intracellular calcium stores or to the activation of Rho kinase. Neither the reassembly of the Golgi complex after BFA removal nor VSV-G transport from ER to the Golgi was altered in cells treated with BDM/ML7 or expressing MRLC2AA. Finally, transport carriers containing Shiga toxin did not move into the cytosol at the tips of comet tails of polymerizing actin. Collectively, the results indicate that 1) myosin motors move to transport carriers from the Golgi complex to the ER along actin filaments; 2) nonmuscle myosin II mediates in this process; and 3) actin comets are not involved in retrograde transport.

scholarly journals 220- and 130-kDa MLCKs have distinct tissue distributions and intracellular localization patterns

2002 ◽  
Vol 282 (3) ◽  
pp. C451-C460 ◽  
Author(s):  
Emily K. Blue ◽  
Zoe M. Goeckeler ◽  
Yijun Jin ◽  
Ling Hou ◽  
Shelley A. Dixon ◽  
...  
Keyword(s):  
Intracellular Trafficking ◽  
Myosin Light Chain ◽  
Adult Mouse ◽  
Intracellular Localization ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Functional Roles ◽  
Nonmuscle Myosin Ii ◽  
Mouse Tissues

To better understand the distinct functional roles of the 220- and 130-kDa forms of myosin light chain kinase (MLCK), expression and intracellular localization were determined during development and in adult mouse tissues. Northern blot, Western blot, and histochemical studies show that the 220-kDa MLCK is widely expressed during development as well as in several adult smooth muscle and nonmuscle tissues. The 130-kDa MLCK is highly expressed in all adult tissues examined and is also detectable during embryonic development. Colocalization studies examining the distribution of 130- and 220-kDa mouse MLCKs revealed that the 130-kDa MLCK colocalizes with nonmuscle myosin IIA but not with myosin IIB or F-actin. In contrast, the 220-kDa MLCK did not colocalize with either nonmuscle myosin II isoform but instead colocalizes with thick interconnected bundles of F-actin. These results suggest that in vivo, the physiological functions of the 220- and 130-kDa MLCKs are likely to be regulated by their intracellular trafficking and distribution.

Essential light chain of Drosophila nonmuscle myosin II

1995 ◽  
Vol 16 (5) ◽  
pp. 491-498 ◽  
Author(s):  
Kevin A. Edwards ◽  
Xiao-Jia Chang ◽  
Daniel P. Kiehart
Keyword(s):  
Light Chain ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Essential Light Chain ◽  
Nonmuscle Myosin Ii

Native nonmuscle myosin II stability and light chain binding inDrosophila melanogaster

2006 ◽  
Vol 63 (10) ◽  
pp. 604-622 ◽  
Author(s):  
Josef D. Franke ◽  
Amanda L. Boury ◽  
Noel J. Gerald ◽  
Daniel P. Kiehart
Keyword(s):  
Light Chain ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii

Blebbistatin, a myosin II inhibitor, suppresses contraction and disrupts contractile filaments organization of skinned taenia cecum from guinea pig

2010 ◽  
Vol 298 (5) ◽  
pp. C1118-C1126 ◽  
Author(s):  
Masaru Watanabe ◽  
Masatoshi Yumoto ◽  
Hideyuki Tanaka ◽  
Hon Hui Wang ◽  
Takeshi Katayama ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Smooth Muscle Contraction ◽  
Myosin Light Chain Phosphorylation ◽  
Thin Filaments ◽  
Tension Development

To explore the precise mechanisms of the inhibitory effects of blebbistatin, a potent inhibitor of myosin II, on smooth muscle contraction, we studied the blebbistatin effects on the mechanical properties and the structure of contractile filaments of skinned (cell membrane permeabilized) preparations from guinea pig taenia cecum. Blebbistatin at 10 μM or higher suppressed Ca2+-induced tension development at any given Ca2+ concentration but had little effects on the Ca2+-induced myosin light chain phosphorylation. Blebbistatin also suppressed the 10 and 2.75 mM Mg2+-induced, “myosin light chain phosphorylation-independent” tension development at more than 10 μM. Furthermore, blebbistatin induced conformational change of smooth muscle myosin (SMM) and disrupted arrangement of SMM and thin filaments, resulting in inhibition of actin-SMM interaction irrespective of activation with Ca2+. In addition, blebbistatin partially inhibited Mg2+-ATPase activity of native actomyosin from guinea pig taenia cecum at around 10 μM. These results suggested that blebbistatin suppressed skinned smooth muscle contraction through disruption of structure of SMM by the agent.

scholarly journals Expansion and concatenation of nonmuscle myosin IIA filaments drive cellular contractile system formation during interphase and mitosis

2016 ◽  
Vol 27 (9) ◽  
pp. 1465-1478 ◽  
Author(s):  
Aidan M. Fenix ◽  
Nilay Taneja ◽  
Carmen A. Buttler ◽  
John Lewis ◽  
Schuyler B. Van Engelenburg ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Molecular Motor ◽  
Myosin Ii ◽  
Cell Movement ◽  
Nonmuscle Myosin ◽  
Contractile Ring ◽  
Contractile System ◽  
Nonmuscle Myosin Ii ◽  
Dividing Cells ◽  
Contractile Forces

Cell movement and cytokinesis are facilitated by contractile forces generated by the molecular motor, nonmuscle myosin II (NMII). NMII molecules form a filament (NMII-F) through interactions of their C-terminal rod domains, positioning groups of N-terminal motor domains on opposite sides. The NMII motors then bind and pull actin filaments toward the NMII-F, thus driving contraction. Inside of crawling cells, NMIIA-Fs form large macromolecular ensembles (i.e., NMIIA-F stacks), but how this occurs is unknown. Here we show NMIIA-F stacks are formed through two non–mutually exclusive mechanisms: expansion and concatenation. During expansion, NMIIA molecules within the NMIIA-F spread out concurrent with addition of new NMIIA molecules. Concatenation occurs when multiple NMIIA-Fs/NMIIA-F stacks move together and align. We found that NMIIA-F stack formation was regulated by both motor activity and the availability of surrounding actin filaments. Furthermore, our data showed expansion and concatenation also formed the contractile ring in dividing cells. Thus interphase and mitotic cells share similar mechanisms for creating large contractile units, and these are likely to underlie how other myosin II–based contractile systems are assembled.

scholarly journals Mammalian Nonmuscle Myosin II Binds to Anionic Phospholipids with Concomitant Dissociation of the Regulatory Light Chain

2016 ◽  
Vol 291 (48) ◽  
pp. 24828-24837 ◽  
Author(s):  
Xiong Liu ◽  
Shi Shu ◽  
Neil Billington ◽  
Chad D. Williamson ◽  
Shuhua Yu ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Ii ◽  
Regulatory Light Chain ◽  
Nonmuscle Myosin ◽  
Anionic Phospholipids ◽  
Nonmuscle Myosin Ii
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