Differential regulation of skeletal muscle myosin‐II and brush border myosin‐I enzymology and mechanochemistry by bacterially produced tropomyosin isoforms

Fanning, Alan S.; Wolenski, Joseph S.; Mooseker, Mark S.; Izant, Jonathan G.

doi:10.1002/cm.970290104

Cited by 88 publications

(70 citation statements)

References 92 publications

(45 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The most extensive data concern the interaction with myosins. The initial indication that Tpms can regulate myosin motor activity came from studies investigating the effect of two different Tpms on a myosin II motor in vitro (Fanning et al, 1994), and showed that myosin II activity depends on the type of Tpm present. Subsequent work demonstrated that Tpm1.6 was able to account for the intracellular location of Myo1b by excluding its interaction with actin filaments that contain Tpm1.6 (Tm2) (Tang and Ostap, 2001).…”

Section: Mechanism Of Function Of Different Tpm Isoformsmentioning

confidence: 99%

Tropomyosin – master regulator of actin filament function in the cytoskeleton

Gunning

Hardeman

Lappalainen

et al. 2015

Journal of Cell Science

225

228

View full text Add to dashboard Cite

Tropomyosin (Tpm) isoforms are the master regulators of the functions of individual actin filaments in fungi and metazoans. Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two Tpm isoforms, whereas mammals have over 40. Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition along its length. Evidence for this 'master regulator' role is based on four core sets of observation. First, spatially and functionally distinct actin filaments contain different Tpm isoforms, and recent data suggest that members of the formin family of actin filament nucleators can specify which Tpm isoform is added to the growing actin filament. Second, Tpms regulate wholeorganism physiology in terms of morphogenesis, cell proliferation, vesicle trafficking, biomechanics, glucose metabolism and organ size in an isoform-specific manner. Third, Tpms achieve these functional outputs by regulating the interaction of actin filaments with myosin motors and actin-binding proteins in an isoform-specific manner. Last, the assembly of complex structures, such as stress fibers and podosomes involves the collaboration of multiple types of actin filament specified by their Tpm composition. This allows the cell to specify actin filament function in time and space by simply specifying their Tpm isoform composition.

show abstract

Section: Mechanism Of Function Of Different Tpm Isoformsmentioning

confidence: 99%

Tropomyosin – master regulator of actin filament function in the cytoskeleton

Gunning

Hardeman

Lappalainen

et al. 2015

Journal of Cell Science

225

228

View full text Add to dashboard Cite

show abstract

“…The expression of tropomyosin isoforms is frequently altered in tumours (Table 1). Some isoforms appear to recruit myosin to actin filaments [80], and influence the activity of the myosin head ATPase and contractility [81]. Tropomyosin has also been reported to increase actin filament stiffness [82] and protect F-actin from the actions of cofilin [83] and gelsolin [84].…”

Section: Acto-myosin Contractionmentioning

confidence: 99%

The actin cytoskeleton in cancer cell motility

Olson

Sahai

2008

Clin Exp Metastasis

484

392

View full text Add to dashboard Cite

Cancer cell metastasis is a multi-stage process involving invasion into surrounding tissue, intravasation, transit in the blood or lymph, extravasation, and growth at a new site. Many of these steps require cell motility, which is driven by cycles of actin polymerization, cell adhesion and acto-myosin contraction. These processes have been studied in cancer cells in vitro for many years, often with seemingly contradictory results. The challenge now is to understand how the multitude of in vitro observations relates to the movement of cancer cells in living tumour tissue. In this review we will concentrate on actin protrusion and acto-myosin contraction. We will begin by presenting some general principles summarizing the widely-accepted mechanisms for the co-ordinated regulation of actin polymerization and contraction. We will then discuss more recent studies that investigate how experimental manipulation of actin dynamics affects cancer cell invasion in complex environments and in vivo.

show abstract

“…Tm regulates the interaction of actin filaments with actin binding proteins, including myosin, Tn, ADF-cofilin, Arp2/3, formin, and tropomodulin. Tm can activate or inhibit actomyosin, depending on the myosin and Tm isoforms (4)(5)(6)(7). The Tm-dependent regulation is widespread, having been reported in fission yeast and mammalian muscle and nonmuscle systems.…”

mentioning

confidence: 99%

Regulation of actin-myosin interaction by conserved periodic sites of tropomyosin

Barua

Winkelmann

White

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Cooperative activation of actin-myosin interaction by tropomyosin (Tm) is central to regulation of contraction in muscle cells and cellular and intracellular movements in nonmuscle cells. The steric blocking model of muscle regulation proposed 40 y ago has been substantiated at both the kinetic and structural levels. Even with atomic resolution structures of the major players, how Tm binds and is designed for regulatory function has remained a mystery. Here we show that a set of periodically distributed evolutionarily conserved surface residues of Tm is required for cooperative regulation of actomyosin. Based on our results, we propose a model of Tm on a structure of actin-Tm-myosin in the "open" (on) state showing potential electrostatic interactions of the residues with both actin and myosin. The sites alternate with a second set of conserved surface residues that are important for actin binding in the inhibitory state in the absence of myosin. The transition from the closed to open states requires the sites identified here, even when troponin + Ca 2+ is present. The evolutionarily conserved residues are important for actomyosin regulation, a universal function of Tm that has a common structural basis and mechanism.actin filament structure | cell motility | cytoskeleton | muscle contraction | motility assay A ctin and myosin are found in almost all eukaryotic cells and are required for diverse cellular functions, including muscle contraction, cell motility, cell adhesion, cytokinesis, and organelle transport (1). The actin-myosin interaction produces two types of movements: force generation between actin filaments leading to contractions, such as in muscle contraction, cell motility, and cytokinesis; and transport of subcellular organelles and macromolecular complexes by myosin motors along actin filaments. The actomyosin contractile apparatus is best characterized in striated muscle contraction, which is regulated in a Ca 2+ -dependent manner by the proteins, tropomyosin (Tm) and troponin (Tn).Tm is a universal regulator of the actin cytoskeleton. It is a twochained, α-helical coiled-coil actin binding protein that associates end-to-end to form a continuous strand along both sides of actin filaments and regulates the functions and stability of actin filaments (2, 3). Tm regulates the interaction of actin filaments with actin binding proteins, including myosin, Tn, ADF-cofilin, Arp2/3, formin, and tropomodulin. Tm can activate or inhibit actomyosin, depending on the myosin and Tm isoforms (4-7). The Tm-dependent regulation is widespread, having been reported in fission yeast and mammalian muscle and nonmuscle systems. The regulation of actomyosin by Tm may be viewed as universal, although there is little understanding of the mechanism or structural basis, the focus of the present work.In striated muscle, regulation of myosin binding to the thin filament (actin-Tm-Tn) is described by a three-state model, where the three kinetic states are thought to correspond to three positions of Tm on the actin filament (8-1...

show abstract

Differential regulation of skeletal muscle myosin‐II and brush border myosin‐I enzymology and mechanochemistry by bacterially produced tropomyosin isoforms

Cited by 88 publications

References 92 publications

Tropomyosin – master regulator of actin filament function in the cytoskeleton

Tropomyosin – master regulator of actin filament function in the cytoskeleton

The actin cytoskeleton in cancer cell motility

Regulation of actin-myosin interaction by conserved periodic sites of tropomyosin

Contact Info

Product

Resources

About