Description
Actin, with a molecular weight of 42 kDa, is a globular, multifunctional protein that forms microfilaments and is present in virtually all eukaryotic cells. In mammals, at least six actin isoforms are encoded by distinct genes, categorized into three classes (α, β, and γ) based on their isoelectric points. Generally, α-actins are found in muscle tissues (α-skeletal, α-aortic smooth, α-cardiac), while β and γ isoforms predominate in non-muscle cells (β-cytoplasmic, γ1-cytoplasmic, γ2-intestinal smooth).
Uses
Actin from rabbit muscle has been used:
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to study its protective role on rabbit muscle lactate dehydrogenase from ascorbate inhibition
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as standard in SDS geland immunoblotting
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in the protein pin array assays
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Used in cell transport studies, and inhibits deoxyribonuclease I
Uses
Actin from bovine muscle has been used as an internal standard and positive control during western blotting.
General Description
Actin is the abundant protein found in many cells which accounts for 10% or more of total protein. Most of the eukaryotic cells shows the presence of actin protein. Outer and inner domains are the two important domains of actin.
Biochem/physiol Actions
Actin is involved in a wide variety of cellular processes like cell migration, phagocytosis, cell polarity and shape. It associates with myosin and aids in muscle contraction. The protein acts as a building block of microfilaments.
Reactivity
Human;Mouse;Rat;Hamster;Monkey;Mink;D. melanogaster ;Zebrafish;Bovine
Background
Actin, a ubiquitous eukaryotic protein, is the major component of the cytoskeleton. At least six isoforms are known in mammals. Nonmuscle β- and γ-actin, also known as cytoplasmic actin, are ubiquitously expressed, controlling cell structure and motility. While all actin isoforms are highly homologous, cytoplasmic β- and γ-actin protein sequences differ by only four biochemically similar amino acids. For this reason, antibodies raised to β-actin may cross-react with γ-actin, and vice versa. α-cardiac and α-skeletal actin are expressed in striated cardiac and skeletal muscles, respectively; two smooth muscle actins, α- and γ-actin, are found primarily in vascular smooth muscle and enteric smooth muscle, respectively. These actin isoforms regulate the contractile potential of muscle cells. Actin exists mainly as a fibrous polymer, F-actin. In response to cytoskeletal reorganizing signals during processes such as cytokinesis, endocytosis, or stress, cofilin promotes fragmentation and depolymerization of F-actin, resulting in an increase in the monomeric globular form, G-actin. The ARP2/3 complex stabilizes F-actin fragments and promotes formation of new actin filaments. Research studies have shown that actin is hyperphosphorylated in primary breast tumors. Cleavage of actin under apoptotic conditions has been observed in vitro and in cardiac and skeletal muscle, as shown in research studies. Actin cleavage by caspase-3 may accelerate ubiquitin/proteasome-dependent muscle proteolysis.
References
[1] Herman, I.M. (1993) Curr. Opin. Cell Biol. 5, 48-55.
[2] Perrin, B.J. and Ervasti, J.M. (2010) Cytoskeleton (Hoboken) 67, 630-4.
[3] Condeelis, J. (2001) Trends Cell Biol 11, 288-93.
[4] Lim, Y.P. et al. (2004) Clin Cancer Res 10, 3980-7.
[5] Kayalar, C. et al. (1996) Proc Natl Acad Sci U S A 93, 2234-8.
[6] Communal, C. et al. (2002) Proc Natl Acad Sci U S A 99, 6252-6.
[7] Du, J. et al. (2004) J Clin Invest 113, 115-23.
