Heart Failure Reviews

, Volume 10, Issue 3, pp 211–223

Titin: Physiological Function and Role in Cardiomyopathy and Failure


    • Dept. of Veterinary and Comparative Anatomy, Pharmacology, and PhysiologyWashington State University
    • Washington State University
  • Yiming Wu
    • Dept. of Veterinary and Comparative Anatomy, Pharmacology, and PhysiologyWashington State University
  • Labeit Siegfried
    • Institut für Anästhesiologie und Operative IntensivmedizinUniversitätsklinikum Mannheim
  • Martin LeWinter
    • Fletcher Allen Health Care

DOI: 10.1007/s10741-005-5251-7

Cite this article as:
Granzier, H., Wu, Y., Siegfried, L. et al. Heart Fail Rev (2005) 10: 211. doi:10.1007/s10741-005-5251-7


Titin is a giant protein that constitutes the third myofilament of the sarcomere. Single titin molecules anchor in the Z-disk and extend all the way to the M-line region of the sarcomere. Successive titin molecules are arranged head-to-head and tail-to-tail, providing a continuous filament along the full length of the myofibril. The majority of titin's I-band region is extensible and functions as a molecular spring that when extended develops passive force. We will discuss mechanisms for adjusting titin-based force, including alternative splicing and posttranslational modifications. Multiple biological functions can be assigned to different regions of the titin molecule. In addition to titin's role in determining passive muscle stiffness, recent evidence suggests a role in protein metabolism, compartmentalization of metabolic enzymes, binding of chaperones, and positioning of the membrane systems of the T-tubules and sarcoplasmic reticulum. We will also discus titin-based force adjustments that occur in various muscle diseases and several disease-causing titin mutations that have been discovered. We will focus on the role of titin in heart failure patients that was recently investigated in patients with end-stage heart failure due to non-ischemic dilated cardiomyopathy. In end-stage failing hearts, compliant titin isoforms comprise a greater percentage of titin and changes in titin isoform expression in heart failure patients with DCM significantly impact diastolic filling by lowering myocardial stiffness.

Key Words

diastolepassive stiffnesstitin isoformsstretch sensing

Copyright information

© Springer Science + Business Media, Inc. 2005