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Dynamique du cytosquelette de la bordure en brosse des entérocytes : étude par FRAP à deux photons

Abstract : Intestinal epithelial cells contain a brush-like membrane composed of numerous finger-like protuberances called microvilli. Each microvillus is composed of a core bundle containing actin filaments and an helical array of brush border myosin I (BBMI) cross bridges between the plasma membrane and actin filaments. Highly dynamic processes occurs during brush border assembly. In particular, the number and the length of microvilli increase during the final step of adult enterocyte differentiation, as well as during the last stage of embryogenesis. The rapid turnover of cytoskeleton and membrane proteins in the mature enterocytes also suggests that dynamic processes also take place while the enterocyte maintains a stationary morphology. Microvilli dynamics might be driven by the polymerization of actin that is sufficient for example the rocketing motion of bacteria. Alternatively, and non-exclusively, microvilli dynamics might be powered by BBMI either by generating a force as proposed by M. Sheetz during the extension of growth cones filopodia, or by delivering membrane component to the apical domain. In order to elucidate the dynamics of BBMI and actin in the enterocyte brush border, we made an instrument allowing the measurement of tridimensional mobility of proteins in live cells by combining two-photon fluorescence imaging of living cells with fluorescence recovery after photobleaching (FRAP). Ours results show that both actin and BBMI are mobile, but with different dynamics. Moreover, we showed for the first time in living cells that BBMI has a motor activity in microvilli.
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Contributor : François Waharte <>
Submitted on : Friday, November 8, 2002 - 6:14:32 PM
Last modification on : Thursday, December 10, 2020 - 12:31:12 PM
Long-term archiving on: : Friday, April 2, 2010 - 6:31:51 PM


  • HAL Id : tel-00001871, version 1


François Waharte. Dynamique du cytosquelette de la bordure en brosse des entérocytes : étude par FRAP à deux photons. Biophysique []. Université Paris Sud - Paris XI, 2002. Français. ⟨tel-00001871⟩



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