Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myosin is one of the basic structural components of skeletal muscles. Its interaction with actin results in muscle contraction. The myosin molecule is composed of two heavy (MyHC) and two light chains (MyLC) that, together with the adenosine triphosphatase (ATPase) activity, determine the functional characteristics of the fibre. Both MyHC and MyLC present different isoforms. The main MyHC isoforms in adult mammals are the slow MyHC (MyHC-I) and fast MyHCs (MyHC-IIa, MyHC-IIb and MyHC-IIx). Muscle fibres can express only one isoform or coexpress different forms. The muscle phenotype is the product of genome plus environmental stimuli. The family of genes that codifies the MyHC isoforms is located in two different clusters, each isoform being encoded by a separate gene. The gene corresponding to slow MyHC is located in chromosome 14, both in humans and in mice. The other genes are positioned in chromosome 17 in humans, and in chromosome 11 in mice. The transcriptional and translational mechanisms that control the expression of MyHC isoforms are not well known, although it is believed that the main regulation is dependent on mechanical signals. These signals are probably mediated by a biochemical messenger. As a general rule, fast MyHC genes seem to be expressed "by default", whereas the slow MyHC gene would be expressed as a response to changes in load. So far, few studies have analysed the in vivo regulation of MyHC gene expression in respiratory muscles. It has recently been reported that breathing against moderate levels of inspiratory resistance quickly induces an increase in the genetic expression of slow MyHC in the diaphragm. This suggests the possibility of eliciting a phenotypic adaptation of respiratory muscles using specific training protocols.
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PMID:Myosin gene expression in the respiratory muscles. 938 72

The histochemical composition of the levator auris longus (LAL) muscle has been investigated in adult NMRi mice. Histochemical reaction for myofibrillar adenosine triphosphatase (ATPase) after preincubation in alkaline and acidic media, nicotine amideadenine-dinucleotide dehidrogenase (NADH-dehydrogenase), and alpha-glycerophosphate dehydrogenase were performed on cryosections of LAL muscle. Expression of myosin heavy chain (MyHC) isoforms was detected with the immunoperoxidase method applying monoclonal antibodies against MyHC isoforms -1, -2a, -2x/d, and -2b, as well as by sodium dodecylsulfate (SDS) glycerol gel electrophoresis. The muscle was proven to be a pure fast-twitch muscle. The most numerous fibers in LAL muscles contained MyHC-2b and some MyHC-2a. Histochemically, pure IIA fibers with oxidative metabolism and pure IIB fibers with glycolytic metabolism were detected. In contrast to the majority of mature control muscles, numerous hybrid fibers coexpressing MyHC-2x/d with MyHC-2a or MyHC-2b were present. Both hybrids were oxidative-glycolytic; additionally, some hybrids containing MyHC-2a were oxidative. In one out of six muscles, traces of MyHC-1 were detected both with immunoperoxidase staining and with SDS glycerol gel electrophoresis. Rare fibers that exceptionally expressed small amounts of MyHC-1 always coexpressed MyHC-2a, which is an additional proof that pure type I fibers do not exist in LAL. Due to these histochemical characteristics and to its previously described morphological features, the use of the LAL muscle as a model for various studies, particularly muscle and nerve interactions, is emphasized.
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PMID:Fiber types in the mouse levator auris longus muscle: a convenient preparation to study muscle and nerve plasticity. 1068 98