Regulation of Actin Filament Cross-linking and Bundle Shape in Drosophila Bristles
| Autor: | Kelly A. Vranich, Patricia S. Connelly, Michael K. Shaw, Lewis G. Tilney, Gregory M. Guild |
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| Rok vydání: | 2000 |
| Předmět: |
Time Factors
Arp2/3 complex macromolecular substances fascin Microfilament 03 medical and health sciences Actin remodeling of neurons 0302 clinical medicine Okadaic Acid Animals Drosophila Proteins Enzyme Inhibitors actin–membrane interaction forked Actin 030304 developmental biology Fascin 0303 health sciences biology phosphorylation Cell Membrane Microfilament Proteins Actin remodeling Cell Biology Staurosporine Actin cytoskeleton Actins Cell biology actin bundle assembly Actin Cytoskeleton Cross-Linking Reagents Drosophila melanogaster biology.protein Insect Proteins Original Article MDia1 Carrier Proteins 030217 neurology & neurosurgery |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.148.1.87 |
| Popis: | Previous studies demonstrate that in developing Drosophila bristles, two cross-linking proteins are required sequentially to bundle the actin filaments that support elongating bristle cells. The forked protein initiates the process and facilitates subsequent cross-linking by fascin. Using cross-linker–specific antibodies, mutants, and drugs we show that fascin and actin are present in excessive amounts throughout bundle elongation. In contrast, the forked cross-linker is limited throughout bundle formation, and accordingly, regulates bundle size and shape. We also show that regulation of cross-linking by phosphorylation can affect bundle size. Specifically, inhibition of phosphorylation by staurosporine results in a failure to form large bundles if added during bundle formation, and leads to a loss of cross-linking by fascin if added after the bundles form. Interestingly, inhibition of dephosphorylation by okadaic acid results in the separation of the actin bundles from the plasma membrane. We further show by thin section electron microscopy analysis of mutant and wild-type bristles that the amount of material that connects the actin bundles to the plasma membrane is also limited throughout bristle elongation. Therefore, overall bundle shape is determined by the number of actin filaments assembled onto the limited area provided by the connector material. We conclude that assembly of actin bundles in Drosophila bristles is controlled in part by the controlled availability of a single cross-linking protein, forked, and in part by controlled phosphorylation of cross-links and membrane actin connector proteins. |
| Databáze: | OpenAIRE |
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