Structural basis for tropomyosin overlap in thin (actin) filaments and the generation of a molecular swivel by troponin-T

Murakami, Kenji; Stewart, Murray; Nozawa, K.; Tomii, K.; Kudo, Norio; Igarashi, Noriyuki; Shirakihara, Yasuo; Wakatsuki, Soichi; Yasunaga, Takuo; Wakabayashi, T.

doi:10.1073/pnas.0801950105

Cited by 81 publications

(111 citation statements)

References 37 publications

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“…Three different troponin T isoforms were abundant following acclimation to 10°C, 10-20°C and 10-30°C plus heat shock, respectively. Troponin T anchors tropomyosin to the troponin trimer complex, and in conjunction with actin, is responsible for producing the 'swivel' effect in muscles (Myers et al, 1996;Murakami et al, 2008). Thereby, troponin T is thought to organize the regulatory complex of actin filaments (Clark et al, 2002).…”

Section: Actin-binding Proteinsmentioning

confidence: 99%

The proteomic response of cheliped myofibril tissue in the eurythermal porcelain crab Petrolisthes cinctipes to heat shock following acclimation to daily temperature fluctuations

Garland

Stillman

Tomanek

2015

Journal of Experimental Biology

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The porcelain crab Petrolisthes cinctipes lives under rocks and in mussel beds in the mid-intertidal zone where it experiences immersion during high tide and saturating humid conditions in air during low tide, which can increase habitat temperature by up to 20°C. To identify the biochemical changes affected by increasing temperature fluctuations and subsequent heat shock, we acclimated P. cinctipes for 30 days to one of three temperature regimes: (1) constant 10°C, (2) daily temperature fluctuations between 10 and 20°C (5 h up-ramp to 20°C, 1 h down-ramp to 10°C) and (3) 10-30°C (up-ramp to 30°C). After acclimation, animals were exposed to either 10°C or a 30°C heat shock to analyze the proteomic changes in claw muscle tissue. Following acclimation to 10-30°C (measured at 10°C), enolase and ATP synthase increased in abundance. Following heat shock, isoforms of arginine kinase and glycolytic enzymes such as aldolase, triose phosphate isomerase and glyceraldehyde 3-phosphate dehydrogenase increased across all acclimation regimes. Full-length isoforms of hemocyanin increased abundance following acclimation to 10-30°C, but hemocyanin fragments increased after heat shock following constant 10°C and fluctuating 10-20°C, possibly playing a role as antimicrobial peptides. Following constant 10°C and fluctuating 10-20°C, paramyosin and myosin heavy chain type-B increased in abundance, respectively, whereas myosin light and heavy chain decreased with heat shock. Actin-binding proteins, which stabilize actin filaments (filamin and tropomyosin), increased during heat shock following 10-30°C; however, actin severing and depolymerization proteins (gelsolin and cofilin) increased during heat shock following 10-20°C, possibly promoting muscle fiber restructuring. RAF kinase inhibitor protein and prostaglandin reductase increased during heat shock following constant 10°C and fluctuating 10-20°C, possibly inhibiting an immune response during heat shock. The results suggest that ATP supply, muscle fiber restructuring and immune responses are all affected by temperature fluctuations and subsequent acute heat shock in muscle tissue. Furthermore, although heat shock after acclimation to constant 10°C and fluctuating 10-30°C showed the greatest effects on the proteome, moderately fluctuating temperatures (10-20°C) broadened the temperature range over which claw muscle was able to respond to an acute heat shock with limited changes in the muscle proteome. INTRODUCTIONEnvironmental temperature has a ubiquitous effect on rates of biochemical reactions and cellular structures in ectothermic organisms, which have adapted their cellular processes and structures to cope with the specific thermal properties of their habitat (Somero, 2012;Tomanek, 2010). An organism's ability to adjust biochemical processes to different body temperatures is in large part determined by the rate and amplitude of temperature change and its evolutionary history, e.g. the thermal environment it occupies and recent thermal history, e.g. acclimatization. For...

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Section: Actin-binding Proteinsmentioning

confidence: 99%

The proteomic response of cheliped myofibril tissue in the eurythermal porcelain crab Petrolisthes cinctipes to heat shock following acclimation to daily temperature fluctuations

Garland

Stillman

Tomanek

2015

Journal of Experimental Biology

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“…N and C depict N-and C-terminal protein ends, respectively. Dark-blue tropomyosin depicts near-neighbor tropomyosin dimer interaction (Greenfield et al 2006;Murakami et al 2008). Myosin-S1 is depicted in solid green (light-green myosin-S1 to better understand its transition states).…”

Section: C-terminal Region Of Mybp-cmentioning

confidence: 99%

“…This diagram is based on the structure of actin subdomains (Kabsch et al 1990;Murakami et al 2010), the position of tropomyosin on F-actin (Lehman et al 2000;Pirani et al 2005;Vibert et al 1997) and the core domain of human troponin (Takeda et al 2003;Vinogradova et al 2005). The tropomyosin overlap region (head-to-tail) depicts interaction with near-neighbor tropomyosin dimer (dark-blue) (Greenfield et al 2006;Murakami et al 2008). The orientation of thin filament proteins is as follows: the N-terminal region of cardiac troponin T points towards the pointed end (M-band), while the core domain of the troponin complex is oriented to the barbed end (Z-disk) (Paul et al 2009).…”

Section: Current Conceptions Of the Mechanisms Underlying Length-depementioning

confidence: 99%

Historical perspective on heart function: the Frank–Starling Law

Sequeira

Velden

2015

Biophys Rev

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More than a century of research on the FrankStarling Law has significantly advanced our knowledge about the working heart. The Frank-Starling Law mandates that the heart is able to match cardiac ejection to the dynamic changes occurring in ventricular filling and thereby regulates ventricular contraction and ejection. Significant efforts have been attempted to identify a common fundamental basis for the Frank-Starling heart and, although a unifying idea has still to come forth, there is mounting evidence of a direct relationship between length changes in individual constituents (cardiomyocytes) and their sensitivity to Ca 2+ ions. As the Frank-Starling Law is a vital event for the healthy heart, it is of utmost importance to understand its mechanical basis in order to optimize and organize therapeutic strategies to rescue the failing human heart. The present review is a historic perspective on cardiac muscle function. We Brevive^a century of scientific research on the heart's fundamental protein constituents (contractile proteins), to their assemblies in the muscle (the sarcomeres), culminating in a thorough overview of the several synergistically events that compose the Frank-Starling mechanism. It is the authors' personal beliefs that much can be gained by understanding the Frank-Starling relationship at the cellular and whole organ level, so that we can finally, in this century, tackle the pathophysiologic mechanisms underlying heart failure.

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“…Muscle contraction is triggered by the influx of Ca 2ϩ into the sarcoplasm, where it binds to TnC and initiates a sequence of conformational changes through TnI and TnT. The ensuing conformational shift of TnT and its interaction with Tm (11) results in azimuthal movement of Tm and partial uncovering of the myosin-binding sites of actin. This is called the closed state.…”

mentioning

confidence: 99%

Mechanistic Heterogeneity in Contractile Properties of α-Tropomyosin (TPM1) Mutants Associated with Inherited Cardiomyopathies

Gupte

Haque

Gangadharan

et al. 2015

Journal of Biological Chemistry

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Background: Single residue substitutions in sarcomeric proteins cause most inherited cardiomyopathies. Results: Mutant ␣-tropomyosins cause multiple functional alterations in actin affinity and Ca 2ϩ sensitivity. Conclusion: Mutants follow distinct mechanisms to change Ca 2ϩ sensitivity. Significance: Fluorescence assays to measure changes in troponin C conformation may provide a simple platform for preliminary high throughput screening of modulatory small molecules to treat inherited cardiomyopathies.

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Structural basis for tropomyosin overlap in thin (actin) filaments and the generation of a molecular swivel by troponin-T

Cited by 81 publications

References 37 publications

The proteomic response of cheliped myofibril tissue in the eurythermal porcelain crab Petrolisthes cinctipes to heat shock following acclimation to daily temperature fluctuations

The proteomic response of cheliped myofibril tissue in the eurythermal porcelain crab Petrolisthes cinctipes to heat shock following acclimation to daily temperature fluctuations

Historical perspective on heart function: the Frank–Starling Law

Mechanistic Heterogeneity in Contractile Properties of α-Tropomyosin (TPM1) Mutants Associated with Inherited Cardiomyopathies

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