1. Tropomyosin was prepared from fresh human myocardium and antisera raised in rabbits. A sensitive radioimmunoassay was developed for the detection of human cardiac tropomyosin in human sera down to levels of 1 ng/ml. 2. Values for human cardiac tropomyosin in normal patients ranged from less than 1 to 3 ng/ml. In 18 patients with acute myocardial infarction all had elevated tropomyosin levels...

Tropomyosin is a coiled-coil protein that polymerizes by head-to-tail interactions in an ionic strength-dependent manner. We produced a recombinant full-length chicken alpha-tropomyosin containing a 5-hydroxytryptophan residue at position 269 (formerly an alanine), 15 residues from the C terminus, and show that its fluorescence intensity specifically reports tropomyosin head-to-tail interaction...

In striated muscle, regulation of actin-myosin interactions depends on a series of conformational changes within the thin filament that result in a shifting of the tropomyosin-troponin complex between distinct locations on actin. The major factors activating the filament are Ca(2+) and strongly bound myosin heads. Many lines of evidence also point to an active role of actin in the regulation. I...

A family of sulfonyl-hydrazone (Shz) small molecules including shz-1 was found to induce Nkx2.5 gene and subsequently -tropomyosin in P19CL6 cells. In order to understand the mechanism by which shz-1 ropomyosin , we employed Mexican axolotl ( Ambystoma mexicanum ) as the animal model, which we use in our laboratory for studying the structural/functional relationship of tropomyosin in relation t...

Assembly of the actin cytoskeleton is an important part of formation of neurites in developing neurons. Tropomodulin, a tropomyosin-dependent capping protein for the pointed end of the actin filament, is one of the key players in this process. Tropomodulin binds tropomyosin in two binding sites. Tmod1 and Tmod2, tropomodulin isoforms found in neurons, were overexpressed in PC12 cells, a model s...

background: dermatophagoides farinae and dermatophagoides pteronyssinus are house dust mites (hdm) that they cause severe asthma and allergic symptoms. tropomyosin protein plays an important role in mentioned immune and allergic reactions to hdms. here, tropomyosin protein from dermatophagoides spp. was comprehensively screened in silico for its allergenicity, antigenicity and similarity/conser...

Tropomyosin is a regulatory protein associated with F-actin in many actomyosin contractile systems. If in vitro conditions are such that tropomyosin binds only slightly to F-actin, then the addition of myosin heads can induce stoichiometric binding between them. This suggests that formation of rigor bonds between actin and myosin heads may cause some change in the actin, stabilizing the appropr...

The lens fiber cells express all the major components of the erythrocyte membrane skeleton including spectrin, protein 4.1 and ankyrin. We have used immunoblot and immunoprecipitation analyses, as well as immunofluorescence localization to identify and characterize two additional components of the membrane skeleton in the rat lens: tropomyosin and the tropomyosin-binding protein tropomodulin. I...

RATIONALE Ca(2+) control of troponin-tropomyosin position on actin regulates cardiac muscle contraction. The inhibitory subunit of troponin, cardiac troponin (cTn)I is primarily responsible for maintaining a tropomyosin conformation that prevents crossbridge cycling. Despite extensive characterization of cTnI, the precise role of its C-terminal domain (residues 193 to 210) is unclear. Mutations...