Stehle, Robert and Tesi, Chiara (2017). Kinetic coupling of phosphate release, force generation and rate-limiting steps in the cross-bridge cycle. J. Muscle Res. Cell Motil., 38 (3-4). S. 275 - 290. DORDRECHT: SPRINGER. ISSN 1573-2657
Full text not available from this repository.Abstract
A basic goal in muscle research is to understand how the cyclic ATPase activity of cross-bridges is converted into mechanical force. A direct approach to study the chemo-mechanical coupling between P-i release and the force-generating step is provided by the kinetics of force response induced by a rapid change in [P-i]. Classical studies on fibres using caged-P-i discovered that rapid increases in [P-i] induce fast force decays dependent on final [P-i] whose kinetics were interpreted to probe a fast force-generating step prior to P-i release. However, this hypothesis was called into question by studies on skeletal and cardiac myofibrils subjected to P-i jumps in both directions (increases and decreases in [P-i]) which revealed that rapid decreases in [P-i] trigger force rises with slow kinetics, similar to those of calcium-induced force development and mechanically-induced force redevelopment at the same [P-i]. A possible explanation for this discrepancy came from imaging of individual sarcomeres in cardiac myofibrils, showing that the fast force decay upon increase in [P-i] results from so-called sarcomere 'give'. The slow force rise upon decrease in [P-i] was found to better reflect overall sarcomeres cross-bridge kinetics and its [P-i] dependence, suggesting that the force generation coupled to P-i release cannot be separated from the rate-limiting transition. The reasons for the different conclusions achieved in fibre and myofibril studies are re-examined as the recent findings on cardiac myofibrils have fundamental consequences for the coupling between P-i release, rate-limiting steps and force generation. The implications from P-i-induced force kinetics of myofibrils are discussed in combination with historical and recent models of the cross-bridge cycle.
Item Type: | Journal Article | ||||||||||||
Creators: |
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URN: | urn:nbn:de:hbz:38-222113 | ||||||||||||
DOI: | 10.1007/s10974-017-9482-8 | ||||||||||||
Journal or Publication Title: | J. Muscle Res. Cell Motil. | ||||||||||||
Volume: | 38 | ||||||||||||
Number: | 3-4 | ||||||||||||
Page Range: | S. 275 - 290 | ||||||||||||
Date: | 2017 | ||||||||||||
Publisher: | SPRINGER | ||||||||||||
Place of Publication: | DORDRECHT | ||||||||||||
ISSN: | 1573-2657 | ||||||||||||
Language: | English | ||||||||||||
Faculty: | Unspecified | ||||||||||||
Divisions: | Unspecified | ||||||||||||
Subjects: | no entry | ||||||||||||
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Refereed: | Yes | ||||||||||||
URI: | http://kups.ub.uni-koeln.de/id/eprint/22211 |
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