ZBTB17 (MIZ1) Is Important for the Cardiac Stress Response and a Novel Candidate Gene for Cardiomyopathy and Heart Failure.

Background: Mutations in sarcomeric and cytoskeletal proteins are a major cause of hereditary cardiomyopathies, but our knowledge remains incomplete as to how the genetic defects execute their effects.

Methods And Results: We used cysteine and glycine-rich protein 3, a known cardiomyopathy gene, in a yeast 2-hybrid screen and identified zinc-finger and BTB domain-containing protein 17 (ZBTB17) as a novel interacting partner. ZBTB17 is a transcription factor that contains the peak association signal (rs10927875) at the replicated 1p36 cardiomyopathy locus.

Telethonin deficiency is associated with maladaptation to biomechanical stress in the mammalian heart.

Rationale: Telethonin (also known as titin-cap or t-cap) is a 19-kDa Z-disk protein with a unique β-sheet structure, hypothesized to assemble in a palindromic way with the N-terminal portion of titin and to constitute a signalosome participating in the process of cardiomechanosensing. In addition, a variety of telethonin mutations are associated with the development of several different diseases; however, little is known about the underlying molecular mechanisms and telethonin's in vivo function.

Objective: Here we aim to investigate the role of telethonin in vivo and to identify molecular mechanisms underlying disease as a result of its mutation.

MLP (muscle LIM protein) as a stress sensor in the heart.

Muscle LIM protein (MLP, also known as cysteine rich protein 3 (CSRP3, CRP3)) is a muscle-specific-expressed LIM-only protein. It consists of 194 amino-acids and has been described initially as a factor involved in myogenesis (Arber et al. Cell 79:221-231, 1994).

Genetics of mechanosensation in the heart.

Mechanosensation (the ultimate conversion of a mechanical stimulus into a biochemical signal) as well as mechanotransduction (transmission of mechanically induced signals) belong to the most fundamental processes in biology. These effects, because of their dynamic nature, are particularly important for the cardiovascular system. Therefore, it is not surprising that defects in cardiac mechanosensation, are associated with various types of cardiomyopathy and heart failure.

A common MLP (muscle LIM protein) variant is associated with cardiomyopathy.

Rationale: We previously discovered the human 10T-->C (Trp4Arg) missense mutation in exon 2 of the muscle LIM protein (MLP, CSRP3) gene.

Objective: We sought to study the effects of this single-nucleotide polymorphism in the in vivo situation.

Methods And Results: We now report the generation and detailed analysis of the corresponding Mlp(W4R/+) and Mlp(W4R/W4R) knock-in animals, which develop an age- and gene dosage-dependent hypertrophic cardiomyopathy and heart failure phenotype, characterized by almost complete loss of contractile reserve under catecholamine induced stress.