Titin and troponin: Central players in the Frank-Starling mechanism of the heart

Norio Fukuda*, Takako Terui, Iwao Ohtsuki, Shin'ichi Ishiwata, Satoshi Kurihara

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    39 Citations (Scopus)


    The basis of the Frank-Starling mechanism of the heart is the intrinsic ability of cardiac muscle to produce greater active force in response to stretch, a phenomenon known as length-dependent activation. A feedback mechanism transmitted from cross-bridge formation to troponin C to enhance Ca2+ binding has long been proposed to account for length-dependent activation. However, recent advances in muscle physiology research technologies have enabled the identification of other factors involved in length-dependent activation. The striated muscle sarcomere contains a third filament system composed of the giant elastic protein titin, which is responsible for most passive stiffness in the physiological sarcomere length range. Recent studies have revealed a significant coupling of active and passive forces in cardiac muscle, where titin-based passive force promotes cross-bridge recruitment, resulting in greater active force production in response to stretch. More currently, the focus has been placed on the troponin-based "on-off: switching of the thin filament state in the regulation of length-dependent activation. In this review, we discuss how myocardial lengthdependent activation is coordinately regulated by sarcomere proteins.

    Original languageEnglish
    Pages (from-to)119-124
    Number of pages6
    JournalCurrent Cardiology Reviews
    Issue number2
    Publication statusPublished - 2009


    • Calcium
    • Cardiac muscle
    • Connectin

    ASJC Scopus subject areas

    • Cardiology and Cardiovascular Medicine


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