Troponin I Type 1 - Find me in your slow-twitch skeletal muscles

Wed, 12/31/2014 - 14:39

Troponin I is part of a heteromeric thin filament regulatory complex that is responsible for modulating skeletal and cardiac muscle contraction. Troponin complex consists of three subunits: troponin I (TnI), troponin T (TnT), and troponin C (TnC). Each of these subunits has a different role in the function of the complex. In particular, TnI is the inhibitory component, and confers calcium-sensitivity to the ATPase activity of the myofibril contractile apparatus within striated muscles. By blocking actin-myosin interactions, it regulates muscle relaxation. TnI is encoded by three different genes to produce isoforms that are preferentially expressed as follows: TnI Type 1 (skeletal-slow-twitch), TnI Type 2 (skeletal-fast-twitch), and TnI Type 3 (cardiac). As their names imply, TnI Types 1 and 2 are only expressed in either fast-twitch or slow-twitch skeletal muscle fibers, respectively.

troponin I type I

TnI Type 1 is expressed in cardiac and skeletal muscle during early development but becomes restricted to slow-twitch skeletal muscle fibers upon maturation in adults. Ralli's lab at the UCLA Cardiomyopathy Center used the Troponin I type 1 antibody to study the relationship between hemoglobin (anemia), and the cardiac biomarkers TnI type 3, B-type natriuretic peptide, with regards to risk and mortality in heart failure patients (1). Harmelink et al relied upon immunoblotting with the Troponin I type 1 antibody to demonstrate that the transcription factor MYCN has clear cardiac-specific roles in development and ventricular wall morphogenesis (2). Their studies implicate both bone morphogenetic protein 10 (BMP10) and neuregulin-1 (NRG1) cardiogenic signaling pathways as feeding down into MYCN. Additionally, Chakraborty’s group extensively used the Troponin I type 1 antibody to examine T-box transcription factor (Tbx20)'s ability to promote cardiomyocyte proliferation and preservation of the immature fetal state in adult cells (3).

Novus Biologicals offers Troponin I Type 1 (slow skeletal) reagents for your research needs including:


  1. 16338262
  2. 23063798
  3. 23751911

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