| Autor: |
Hormeño S; Department of Macromolecular Structure, Centro Nacional de Biotecnología, CSIC, Madrid, Spain., Ibarra B, Chichón FJ, Habermann K, Lange BM, Valpuesta JM, Carrascosa JL, Arias-Gonzalez JR |
| Jazyk: |
angličtina |
| Zdroj: |
Biophysical journal [Biophys J] 2009 Aug 19; Vol. 97 (4), pp. 1022-30. |
| DOI: |
10.1016/j.bpj.2009.06.004 |
| Abstrakt: |
The centrosome is the major microtubule-organizing center in animal cells and consists of a pair of centrioles surrounded by a pericentriolar material. We demonstrate laser manipulation of individual early Drosophila embryo centrosomes in between two microelectrodes to reveal that it is a net negatively charged organelle with a very low isoelectric region (3.1 +/- 0.1). From this single-organelle electrophoresis, we infer an effective charge smaller than or on the order of 10(3) electrons, which corresponds to a surface-charge density significantly smaller than that of microtubules. We show, however, that the charge of the centrosome has a remarkable influence over its own structure. Specifically, we investigate the hydrodynamic behavior of the centrosome by measuring its size by both Stokes law and thermal-fluctuation spectral analysis of force. We find, on the one hand, that the hydrodynamic size of the centrosome is 60% larger than its electron microscopy diameter, and on the other hand, that this physiological expansion is produced by the electric field that drains to the centrosome, a self-effect that modulates its structural behavior via environmental pH. This methodology further proves useful for studying the action of different environmental conditions, such as the presence of Ca(2+), over the thermally induced dynamic structure of the centrosome. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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