Evidence for interaction between smooth muscle tropomyosin and caldesmon

Graceffa, Philip

doi:10.1016/0014-5793(87)81034-7

Cited by 67 publications

(36 citation statements)

References 27 publications

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“…Furthermore, MHC organization in individual myofibrils appeared defective, but the overall number of myofibers was similar to the number in control-siRNAtransfected muscle. CaD can interact with F-actin, myosin, calmodulin (CaM) and tropomyosin (TM) (Graceffa, 1987;Smith et al, 1987;Sobue et al, 1981;Sobue and Sellers, 1991;Wang et al, 1997). Moreover, CaD enhances the binding of F-actin to TM and competes with gelsolin, an actin-severing protein that binds to F-actin (Ishikawa et al, 1989;Warren et al, 1994).…”

Section: Discussionmentioning

confidence: 99%

Sox4-mediated caldesmon expression facilitates skeletal myoblast differentiation

Jang

Kim

et al. 2013

Journal of Cell Science

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Summary Caldesmon (CaD), which was originally identified as an actin-regulatory protein, is involved in the regulation of diverse actin-related signaling processes, including cell migration and proliferation, in various cells. The cellular function of CaD has been studied primarily in the smooth muscle system; nothing is known about its function in skeletal muscle differentiation. In this study, we found that the expression of CaD gradually increased as differentiation of C2C12 myoblasts progressed. Silencing of CaD inhibited cell spreading and migration, resulting in a decrease in myoblast differentiation. Promoter analysis of the caldesmon gene (Cald1) and gel mobility shift assays identified Sox4 as a major trans-acting factor for the regulation of Cald1 expression during myoblast differentiation. Silencing of Sox4 decreased not only CaD protein synthesis but also myoblast fusion in C2C12 cells and myofibril formation in mouse embryonic muscle. Overexpression of CaD in Sox4-silenced C2C12 cells rescued the differentiation process. These results clearly demonstrate that CaD, regulated by Sox4 transcriptional activity, contributes to skeletal muscle differentiation.

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Section: Discussionmentioning

confidence: 99%

Sox4-mediated caldesmon expression facilitates skeletal myoblast differentiation

Jang

Kim

et al. 2013

Journal of Cell Science

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“…Skeletal actin was prepared from rabbit skeletal muscle according to Spudich and Watt (1971). Smooth muscle CaD (Lynch and Bretscher, 1986;Wang, 1988), myosin (Ikebe et al, 1978), MLCK (Walsh et al, 1983), and tropomyosin (Graceffa, 1987) were purified from chicken gizzard. Purified smooth muscle myosin was phosphorylated by MLCK as described previously (Zhuang et al, 1995).…”

Section: Methodsmentioning

confidence: 99%

Heat Treatment Could Affect the Biochemical Properties of Caldesmon

Zhuang

Mabuchi

Wang

1996

Journal of Biological Chemistry

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“…4B shows that a small decrease in fluorescence occurred upon the addition of S1 to caldesmon-NBD in the absence of actin. Caldesmon also binds to pure tropomyosin (Graceffa, 1987;Fujii et al, 1988;Watson et al, 1990). Fig.…”

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confidence: 99%

Kinetics of Binding of Caldesmon to Actin

Chalovich

Chen

Dudek

et al. 1995

Journal of Biological Chemistry

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The time course of interaction of caldesmon with actin may be monitored by fluorescence changes that occur upon the binding of 12-(N-methyl-N-(7-nitrobenz-2-oxa-l,3-diazol-4-yl))-labeled caldesmon to actin or to acrylodan actin. The concentration dependence of the observed rate of caldesmon-actin binding was analyzed to a first approximation as a single-step reaction using a Monte Carlo simulation. The derived association and dissociation rates were 10 7 M −1 s −1 and 18.2 s −1 , respectively. Smooth muscle tropomyosin enhances the binding of caldesmon to actin, and this was found to be due to a reduction in the rate of dissociation to 6.3 s −1 . There is no evidence from this study for a different mechanism of binding in the presence of tropomyosin. The fluorescence changes that occurred with the binding of 12-(N-methyl-N-(7-nitrobenz-2-oxa-l,3-diazol-4-yl))-labeled caldesmon to actin or actin-tropomyosin were reversed by the addition of myosin subfragment 1 as predicted by a competitive binding mechanism.The protein caldesmon inhibits the stimulation of myosin ATPase activity by actin (Dabrowska et al., 1985;Smith and Marston, 1985;Ngai and Walsh, 1985;Sobue et al., 1985). Caldesmon also inhibits force production when added to smooth muscle fibers (Pfitzer et al., 1993) and to skeletal muscle fibers, which normally lack caldesmon (Brenner et al., 1991). Several studies indicate that caldesmon has the potential to modulate contractility (Yamashiro et al., 1990;Walker et al., 1989; Hegmann et al., 1991;Katsuyama et al., 1992) although its primary role as a regulatory protein is not yet proven.We have proposed that an important aspect of the inhibition of ATPase activity by caldesmon is the inhibition of binding of myosin subfragment 1 (S1) 1 to actin in both the presence and absence of tropomyosin (Chalovich et al., 1987;Hemric and Chalovich, 1988;Velaz et al., 1989;Velaz et al, 1990;Chen and Chalovich, 1992). This view is not universally accepted, and other reports suggest that in the presence of tropomyosin and under conditions where S1 concentrations are high relative to caldesmon, inhibition of ATPase activity occurs with little reduction of Sl-ATP binding (Marston and Redwood, 1993). This latter model requires that the mode of action of caldesmon be quite different in the presence of tropomyosin.Testing the different models of caldesmon both by mathematical modeling and by experimentation requires information regarding the rates of binding of caldesmon to actin in the presence and absence of tropomyosin. We have used two combinations of fluorescent * This work was supported by National Institutes of Health Grants AR40540 and AR35216 (to J. M. C.). A preliminary report of this work was presented at the Biophysical Society Meeting, New Orleans, LA, 1994. § To whom correspondence should be addressed. Tel.: 919-816-2973; Fax: 919-816-3383; E-mail: BCCHALOV@ECUVM1.. 1 The abbreviations used are: S1, myosin subfragment 1; NBD, 12-(N-methyl-N-(7-nitrobenz-2-oxa-l,3-diazol-4-yl)); IANBD, N-((2-(iodoacetoxy)...

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Evidence for interaction between smooth muscle tropomyosin and caldesmon

Cited by 67 publications

References 27 publications

Sox4-mediated caldesmon expression facilitates skeletal myoblast differentiation

Sox4-mediated caldesmon expression facilitates skeletal myoblast differentiation

Heat Treatment Could Affect the Biochemical Properties of Caldesmon

Kinetics of Binding of Caldesmon to Actin

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