Actin-facilitated assembly of smooth muscle myosin induces formation of actomyosin fibrils

Applegate, Dianne; Jd, Pardee

doi:10.1083/jcb.117.6.1223

Cited by 39 publications

(29 citation statements)

References 43 publications

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“…Under the activated condition, phosphorylation of caldesmon abolishes its own affinity for myosin (56). As discussed above, binding of myosin monomers to thin filaments could also provide guidance for thick filament formation (1,39).…”

Section: Possible Mechanisms For Thick Filament Assembly In Intact Smmentioning

confidence: 99%

Myosin filament assembly in an ever-changing myofilament lattice of smooth muscle

Seow

2005

American Journal of Physiology-Cell Physiology

111

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Seow, Chun Y. Myosin filament assembly in an ever-changing myofilament lattice of smooth muscle. Am J Physiol Cell Physiol 289: C1363-C1368, 2005; doi:10.1152/ajpcell.00329.2005.-A major development in smooth muscle research in recent years is the recognition that the myofilament lattice of the muscle is malleable. The malleability appears to stem from plastic rearrangement of contractile and cytoskeletal filaments in response to stress and strain exerted on the muscle cell, and it allows the muscle to adapt to a wide range of cell lengths and maintain optimal contractility. Although much is still poorly understood, we have begun to comprehend some of the basic mechanisms underlying the assembly and disassembly of contractile and cytoskeletal filaments in smooth muscle during the process of adaptation to large changes in cell geometry. One factor that likely facilitates the plastic length adaptation is the ability of myosin filaments to form and dissolve at the right place and the right time within the myofilament lattice. It is proposed herein that formation of myosin filaments in vivo is aided by the various filament-stabilizing proteins, such as caldesmon, and that the thick filament length is determined by the dimension of the actin filament lattice. It is still an open question as to how the dimension of the dynamic filament lattice is regulated. In light of the new perspective of malleable myofilament lattice in smooth muscle, the roles of many smooth muscle proteins could be assigned or reassigned in the context of plastic reorganization of the contractile apparatus and cytoskeleton. contraction mechanism; length adaptation; thick filament; plasticity; contractile unit THE PRIMARY FUNCTION of smooth muscle in our bodies is to control and regulate the physical dimension and mechanical function of hollow organs. The large volume change in some organs requires that smooth muscle cells lining the organ wall have a large working length range. The length range over which a striated muscle can generate maximal or near maximal force is quite limited (19), between 10% and 20% of the resting muscle length. If smooth muscle were to have the same working length range, the corresponding volume change of the smooth muscle organ would be ϳ30 -70%, which is not adequate for organ functions such as emptying a urinary bladder or pushing a fetus through the birth canal.A broad plateau in the length-force relationship can be observed in many types of smooth muscle. It has been recognized recently that the plateau can become even broader if the muscle is allowed to adapt at each of the lengths at which force measurements are made (48, 69). Different extents of length adaptation in smooth muscle can be induced, at a fixed length, by a single contraction (21, 54), a series of brief activations (48, 55), or a continuous submaximal activation (42) over a period of tens of minutes. Adaptation can also occur in a relaxed muscle set at a fixed length over a period of hours (41, 69) or days (2, 44, 74). In isolated single cells from ...

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Section: Possible Mechanisms For Thick Filament Assembly In Intact Smmentioning

confidence: 99%

Myosin filament assembly in an ever-changing myofilament lattice of smooth muscle

Seow

2005

American Journal of Physiology-Cell Physiology

111

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“…Importantly, myosin filament length is not fixed (26), but rather is dynamically determined, changing even during the course of a single contraction (27,28). In addition, myosin filament length appears to be influenced by recent muscle length history (e.g., length oscillation of relaxed ASM shortens myosin filaments) (29), by the length of actin filaments which seem to provide a template for myosin polymerization (30)(31)(32), and by the phosphorylation state of the 20-kD regulatory myosin light chain (MLC 20 ) (33)(34)(35)(36)(37)(38). We exploited the latter to obtain indirect evidence suggesting that myosin filament length modulates FFIR.…”

Section: Modulation Of Myosin Filament Lengthmentioning

confidence: 99%

Disrupting Actin-Myosin-Actin Connectivity in Airway Smooth Muscle as a Treatment for Asthma?

Lavoie¹,

Dowell²,

Lakser³

et al. 2009

Proceedings of the American Thoracic Society

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Breathing is known to functionally antagonize bronchoconstriction caused by airway muscle contraction. During breathing, tidal lung inflation generates force fluctuations that are transmitted to the contracted airway muscle. In vitro, experimental application of force fluctuations to contracted airway smooth muscle strips causes them to relengthen. Such force fluctuation-induced relengthening (FFIR) likely represents the mechanism by which breathing antagonizes bronchoconstriction. Thus, understanding the mechanisms that regulate FFIR of contracted airway muscle could suggest novel therapeutic interventions to increase FFIR, and so to enhance the beneficial effects of breathing in suppressing bronchoconstriction. Here we propose that the connectivity between actin filaments in contracting airway myocytes is a key determinant of FFIR, and suggest that disrupting actin-myosin-actin connectivity by interfering with actin polymerization or with myosin polymerization merits further evaluation as a potential novel approach for preventing prolonged bronchoconstriction in asthma.

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“…Phosphorylation of MRLC leads to bipolar myosin filaments, resulting in the formation of acto-myosin fibers (Applegate and Pardee, 1992). It has been reported that MRLC is phosphorylated at the cleavage furrow (Matsumura et al, 1998;Murata-Hori et al, 1998;Ueda et al, 2002).…”

Section: Rho Activity Is Required For Accumulation Of Myosin II At Thmentioning

confidence: 99%

Dissecting the Role of Rho-mediated Signaling in Contractile Ring Formation

Kamijo

Ohara

Abe

et al. 2006

MBoC

192

222

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In anaphase, microtubules provide a specification signal for positioning of the contractile ring. However, the nature of the signal remains unknown. The small GTPase Rho is a potent regulator of cytokinesis, but the involvement of Rho in contractile ring formation is disputed. Here, we show that Rho serves as a microtubule-dependent signal that specifies the position of the contractile ring. We found that Rho translocates to the equatorial region before furrow ingression. The Rho-specific inhibitor C3 exoenzyme and small interfering RNA to the Rho GDP/GTP exchange factor ECT2 prevent this translocation and disrupt contractile ring formation, indicating that active Rho is required for contractile ring formation. ECT2 forms a complex with the GTPase-activating protein MgcRacGAP and the kinesinlike protein MKLP1 at the central spindle, and the localization of ECT2 at the central spindle depends on MgcRacGAP and MKLP1. In addition, we show that the bundled microtubules direct Rho-mediated signaling molecules to the furrowing site and regulate furrow formation. Our study provides strong evidence for the requirement of Rho-mediated signaling in contractile ring formation.

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Actin-facilitated assembly of smooth muscle myosin induces formation of actomyosin fibrils

Cited by 39 publications

References 43 publications

Myosin filament assembly in an ever-changing myofilament lattice of smooth muscle

Myosin filament assembly in an ever-changing myofilament lattice of smooth muscle

Disrupting Actin-Myosin-Actin Connectivity in Airway Smooth Muscle as a Treatment for Asthma?

Dissecting the Role of Rho-mediated Signaling in Contractile Ring Formation

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