Identification of a high molecular weight actin-binding protein in skeletal muscle.

A high molecular weight actin-binding protein was isolated from the Physarum polycephalum plasmodia. The protein ( HMWP ) shares many properties with other high molecular weight actin-binding proteins such as spectrin, actin-binding protein from macrophages, and filamin. It has a potent activity to cross-link F-actin into a gel-like structure. Its cross-linking activity does not depend on calcium concentrations. Hydrodynamic studies have revealed that the protein is in the monomeric state of a polypeptide chain with molecular weight of approximately 230,000 in a high ionic strength solvent, while it self-associates into a dimer under physiological ionic conditions. Electron microscopic examinations of HMWP have shown that the monomer particle observed in a high ionic strength solvent is rod shaped with the two-stranded morphology very similar to that of spectrin. On the other hand, under physiological ionic conditions, the HMWP dimer shows the dumb-bell shape with two globular domains connected with a thin flexible strand.

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Further Characterization of a Brain High Molecular Weight Actin-Binding Protein (BABP): Interaction with Brain Actin and Ultrastructural Studies

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a134253 ◽

1983 ◽

Vol 93 (4) ◽

pp. 977-987 ◽

Cited By ~ 10

Author(s):

Tadashi SHIMO-OKA ◽

Kazuo OHNISHI ◽

Yoshio WATANABE

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Binding Protein ◽

Actin Binding ◽

Actin Binding Protein ◽

Ultrastructural Studies

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Stimulation of Actomyosin Mg2+-ATPase Activity by a Brain Microtubule-Associated Protein Fraction. High-Molecular-Weight Actin-Binding Protein Is the Stimulating Factor

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a133595 ◽

1981 ◽

Vol 90 (5) ◽

pp. 1297-1307 ◽

Cited By ~ 42

Author(s):

Tadashi SHIMO-OKA ◽

Yoshio WATANABE

Keyword(s):

Molecular Weight ◽

Atpase Activity ◽

High Molecular Weight ◽

Protein Fraction ◽

Binding Protein ◽

Actin Binding ◽

Actin Binding Protein ◽

Stimulating Factor ◽

Stimulation Of

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Phosphorylation Of Platelet Actin-Binding Protein During Platelet Activation

10.1055/s-0038-1652791 ◽

1981 ◽

Author(s):

Roger C Carroll ◽

Jonathan M Gerrard

Keyword(s):

Molecular Weight ◽

Platelet Activation ◽

Time Course ◽

Binding Protein ◽

Sodium Dodecyl ◽

Apparent Molecular Weight ◽

Actin Binding ◽

Actin Binding Protein ◽

Platelet Protein ◽

External Calcium

We have followed the 32P-labelling of actin-binding protein as a function of platelet activation. Utilizing polyacrylamide sodium dodecyl sulfate gel electrophoresis to resolve total platelet protein samples we found 2 to 3 fold labelling increases in actin-binding protein 30 to 60 seconds after thrombin stimulation. Somewhat larger increases were observed for 40,000 and 20,000 apparent molecular weight peptides. The actin-binding protein was identified on the gels by coelectrophoresis of purified actin-binding protein as well as cytoskeletal cores prepared by detergent extraction of activated 32p-iabelled platelets. In addition, these cytoskeletal cores indicated that the 32P-labelled actin-binding protein was closely associated with the activated platelet's cytoskeleton. Following the 32P-labelling of actin-binding protein over an 8 minute time course revealed that in aggregating platelet samples rapid desphosphorylation to almost initial levels occurred between 3 and 5 minutes. A similar curve was obtained for the 20,000 apparent molecular weight peptide. This rapid dephosphorylation was shown to be dependent on platelet aggregation in the absence of external calcium or in thrombastenic platelets lacking the aggregation response to activation. These results suggest that phosphorylation of actin-binding protein initiates its association with the platelet cytoskeleton during activation.

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