Actin Filament Turnover Regulated by Cross-linking Accounts for the Size, Shape, Location, and Number of Actin Bundles in Drosophila Bristles
AUTOR(ES)
Tilney, Lewis G.
FONTE
The American Society for Cell Biology
RESUMO
Drosophila bristle cells are shaped during growth by longitudinal bundles of cross-linked actin filaments attached to the plasma membrane. We used confocal and electron microscopy to examine actin bundle structure and found that during bristle elongation, snarls of uncross-linked actin filaments and small internal bundles also form in the shaft cytoplasm only to disappear within 4 min. Thus, formation and later removal of actin filaments are prominent features of growing bristles. These transient snarls and internal bundles can be stabilized by culturing elongating bristles with jasplakinolide, a membrane-permeant inhibitor of actin filament depolymerization, resulting in enormous numbers of internal bundles and uncross-linked filaments. Examination of bundle disassembly in mutant bristles shows that plasma membrane association and cross-bridging adjacent actin filaments together inhibits depolymerization. Thus, highly cross-bridged and membrane-bound actin filaments turn over slowly and persist, whereas poorly cross-linked filaments turnover more rapidly. We argue that the selection of stable bundles relative to poorly cross-bridged filaments can account for the size, shape, number, and location of the longitudinal actin bundles in bristles. As a result, filament turnover plays an important role in regulating cytoskeleton assembly and consequently cell shape.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=206991Documentos Relacionados
- Cross-linking reconsidered: binding and cross-linking fields and the cellular response.
- Size, shape, and the thermal niche of endotherms
- In vivo covalent cross-linking of cellular actin by the Vibrio cholerae RTX toxin
- Tracer diffusion through F-actin: effect of filament length and cross-linking.
- Chemical cross-linking of Chlamydia trachomatis.