and [alpha]-actinin (190 kDa) are ubiquitously expressed structural proteins of the Z-line.
The team found that the faulty titin
gene may also play a role in the condition.
: central player of hypertrophic signaling and sarcomeric protein quality control," Biological Chemistry, vol.
This reduced PKG activity in adjacent cardiomyocytes leading to hypophosphorylation of the contractile protein, titin
.  This leads to impaired relaxation of the sarcomere and consequently HFnEF.
An example is that a gene variant of the muscle protein titin
is associated with enlarged hearts and heart failure.
The passive process consists of cardiac chamber compliance that is reduced by the expression and cross-linking of collagen in the interstitium and alterations in titin
expression within sarcomeres when the ventricle stiffens .
Trombitas et al., "Changes in titin
isoform expression in pacing-induced cardiac failure give rise to increased passive muscle stiffness," Circulation, vol.
Acetylcholine receptor (AChR) antibodies are most common and occur in 85% of patients ; however, small proportion of patients have other antibodies such as muscle specific kinase antibodies (anti-MuSK), antismooth muscle antibodies, and striational antibodies (antimuscle titin
and anti-ryanodine receptor) .
PKG acutely reduces cardiomyocyte stiffness through phosphorylation of the giant protein titin
, the most important regulator of passive myocardial stiffness.
Ikonomidis et al., "Myocardial stiffness in patients with heart failure and a preserved ejection fraction contributions of collagen and titin
," Circulation, vol.
Greaser et al., "RBM20, a gene for hereditary cardiomyopathy, regulates titin
splicing," Nature Medicine, vol.
Based on a mutation similar to the mKIAA0657 protein (titin
, TTN), we hypothesized that the pressure of the strong selection for high marbling in Japanese Black breed increases the frequencies of the T, among T and A alleles at the TTN g.231054C > T, RPL27A g.3109537C > T and ankirin 2 genes c.*188G > A SNPs, respectively (Watanabe et al., 2011).