PNAS Plus Significance Statements An invertebrate smooth muscle with striated muscle myosin filaments
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چکیده
All animals have the ability to move. In most animals, striated muscles move the body and smooth muscles the internal organs. In both muscles, contraction results from interaction between myosin and actin filaments. Based on vertebrate studies, smooth and striated muscles are thought to have different protein components and filament structures. We have studied muscle ultrastructure in the parasite Schistosoma mansoni, where we find that this view is not supported. This invertebrate possesses only smooth muscles, yet its myosin sequence and filament structure are identical to those of striated muscle, while its actin filaments are smooth muscle-like. Such “hybrid” muscles may be common in other invertebrates. This finding challenges the paradigm that smooth and striated muscles always have different components. (See pp. E5660–E5668.)
منابع مشابه
An invertebrate smooth muscle with striated muscle myosin filaments.
Muscle tissues are classically divided into two major types, depending on the presence or absence of striations. In striated muscles, the actin filaments are anchored at Z-lines and the myosin and actin filaments are in register, whereas in smooth muscles, the actin filaments are attached to dense bodies and the myosin and actin filaments are out of register. The structure of the filaments in s...
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