The control of cellular shape and motility. Mg2+ and tropomyosin regulate the formation and the dissociation of microfilament bundles.
At pH 7.14 and 37 degrees C, in 7.2% (w/v) poly(ethylene glycol) 6000, tropomyosin-regulated actin filaments are converted into filament bundles by increasing the free Mg2+ concentration to 1.7-2.0 mM. When free Mg2+ concentration is decreased below 1.7 mM, bundles dissociate back into tropomyosin-regulated actin filaments. Pure actin filaments are insensitive to this mechanism of control and are found as filament bundles in all the range of free Mg2+ concentrations tested (1.37-2.2 mM). The mechanism of regulation described above is likely to operate in the cell, where the concentration of free Mg2+ is linked to the energy charge of the adenine nucleotide system.
Grazi
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Istituto di Chimica Biologica, Università di Ferrara, Italy.
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Cataldi
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D008841:Actin Cytoskeleton / Q000378:metabolism / Q000502:physiology*; D000199:Actins / Q000096:biosynthesis / Q000502:physiology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002465:Cell Movement / Q000502:physiology; D048429:Cell Size / Q000502:physiology; D002645:Chickens; D007700:Kinetics; D046911:Macromolecular Substances; D008274:Magnesium / Q000502:physiology*; D008840:Microfilament Proteins / Q000096:biosynthesis / Q000502:physiology*; D009132:Muscles / Q000166:cytology* / Q000502:physiology; D011092:Polyethylene Glycols / Q000494:pharmacology; D011817:Rabbits; D014335:Tropomyosin / Q000378:metabolism / Q000502:physiology*
D000199:Actins; D046911:Macromolecular Substances; D008840:Microfilament Proteins; D014335:Tropomyosin; C052523:actin filament bundling proteins; D011092:Polyethylene Glycols; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D008274:Magnesium