798 actin undergoes rapid and reversible polymerization associated with platelet shape change

ABSTRACT Platelets undergo dramatic cytoskeletal changes following activation. Previous studies have suggested that these changes are related to the conversion of actin from monomeric (G) to

the filamentous (F) form. The present study was designed to determine the polymerization state of actin under conditions associated with platelet shape change without aggregation, in the

presence and absence of inhibitors of shape change. Cytochalasin D (CD) is an agent which inhibits platelet shape change as well as actin polymerization in vitro. EDTA-treated, gel-filtered

platelets were exposed to the experimental conditions described below prior to Triton lysis. G-actin was measured by the DNAse assay of Blikstad et al. Total cellular actin was determined by

assay of lysates exposed to guanidine HC1. Results were expressed as % of total actin measurable as G-actin ± SEM as follows: (1)unstimulated 67.5±1.4, n=32, (2)thrombin-stimulated

36.8±1.2, n=25, (3)CD-treated (before thrombin) 62.4±2.1, n=21, (4)CD-treated (after thrombin) 69.4±2.0, n=8, (5)ADP-stimulated 44.0±1.0, n=4, (6)Adenosine-treated (prior to ADP) 63.0±3.1,

n=4, (7)CD-treated (prior to ADP) 66.8±5.7, n=4. These findings indicate that platelet actin is reversibly transformed from G-actin to F-actin during shape change. This transformation is

blocked both by a drug which competitively inhibits stimulation and shape change (adenosine), and a drug which inhibits actin polymerization and shape change (CD). ARTICLE PDF AUTHOR

INFORMATION AUTHORS AND AFFILIATIONS * The Johns Hopkins Univ., Dept. of Biophysics, and The Johns Hopkins Hospital, Dept. of Pediatrics, Baltimore James F Casella, Shin Lin & William H

Zinkham Authors * James F Casella View author publications You can also search for this author inPubMed Google Scholar * Shin Lin View author publications You can also search for this author

inPubMed Google Scholar * William H Zinkham View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS

ARTICLE CITE THIS ARTICLE Casella, J., Lin, S. & Zinkham, W. 798 ACTIN UNDERGOES RAPID AND REVERSIBLE POLYMERIZATION ASSOCIATED WITH PLATELET SHAPE CHANGE. _Pediatr Res_ 15 (Suppl 4),

575 (1981). https://doi.org/10.1203/00006450-198104001-00822 Download citation * Issue Date: 01 April 1981 * DOI: https://doi.org/10.1203/00006450-198104001-00822 SHARE THIS ARTICLE Anyone

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