Actin: Difference between revisions
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{{STRUCTURE_3hbt| PDB=3hbt | SIZE=400| SCENE=Actin/Cv/1 |right|CAPTION=Native G-actin with methyl-histidine complex with ATP, sulfate and Ca+2 ion (green) [[3hbt]] }} | {{STRUCTURE_3hbt| PDB=3hbt | SIZE=400| SCENE=Actin/Cv/1 |right|CAPTION=Native G-actin with methyl-histidine complex with ATP, sulfate and Ca+2 ion (green) [[3hbt]] }} | ||
[[Actin]] is a protein found in all eukaryotic cells. It is the monomer of two types of filaments: microfilaments which are part of the cytoskeleton and thin filaments which are part of muscles. Three isoforms of actin are identified: α (Aa) (or G-actin) found in muscle tissue, β (Ab) and γ (Ag) actins are components of the cytoskeleton. F-actin is Aa bound to ATP | [[Actin]] is a protein found in all eukaryotic cells. It is the monomer of two types of filaments: microfilaments which are part of the cytoskeleton and thin filaments which are part of muscles. Three isoforms of actin are identified: α (Aa) (or G-actin) found in muscle tissue, β (Ab) and γ (Ag) actins are components of the cytoskeleton. F-actin is Aa bound to ATP. For more details see:<br /> *[[F-actin]]<br /> *[[Non-polymerizable monomeric actin]].<br /> <scene name='Actin/Cv/2'>Click here to see the difference between 2 conformations of bovine Ag actin</scene> (PDB entries [[1hlu]] and [[2btf]]; morph was taken from [http://molmovdb.org/cgi-bin/movie.cgi Gallery of Morphs] of the [http://molmovdb.org Yale Morph Server]). | ||
== Function == | |||
Actin participates in muscle contraction, cell motility, cell division and cytokinesis. Actin associated with myosin is responsible for most cell movements. | |||
== Disease == | |||
Mutations in α-actin found in skeletal striated muscles can cause myopathy. Mutations in α-actin found in smooth muscles can cause thoracic aortic aneurism. Mutations in α-actin found in heart muscles can cause heart malfunctioning. | |||
== Structural highlights == | |||
Actin binds ATP in a cleft. It changes its conformation upon hydrolysis of its bound ATP to ADP. Actin filaments are polar. They are formed with all monomers having their clefts pointing in the same direction. | |||
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