Abstracts
Résumé
La fonction essentielle d’un neurone est de recevoir, conduire, transmettre et intégrer les influx nerveux. Dans ce but, la majorité des neurones va développer plusieurs dendrites et un unique axone, prolongements qui diffèrent par leur structure moléculaire et par leur rôle: les premières reçoivent l’information, alors que le second la propage. La polarisation structurale et fonctionnelle commence peu après le début de croissance des neurites. Les mécanismes responsables de la mise en place de la polarité neuronale sont dans l’ensemble encore inconnus. Cependant, les membres de la famille des petites GTPases Rho ont récemment été impliqués dans la régulation de la morphologie neuronale, dont le développement de la polarité neuronale, la croissance et le guidage axonal, l’élaboration de l’arbre dendritique, la plasticité synaptique… De plus, les protéines Rho paraissent impliquées, directement ou indirectement, dans certaines maladies neurologiques telles que le retard mental lié à l’X et les maladies d’Alzheimer et de Parkinson. Ces observations suggèrent l’importance de ces protéines dans le développement, le maintien et le fonctionnement du système nerveux.
Summary
Neurons possess a polarized morphology. In general, each neuron has several dendrites but only one axon. Such morphology is the basis for directionalized rapid signaling, information flowing from the short dendrites to the long axon. The mechanisms involved in the establishment of the neuronal polarity remain largely unknown. However, recently, members of Rho family proteins have been implicated in the regulation of neuronal morphology especially development of neuronal polarity, axon outgrowth and guidance, dendritic tree elaboration and synapse formation. Moreover, the Rho GTPases have been reported to be directly or indirectly involved in some neurological conditions such as X-linked mental retardation as well as Alzheimer’s and Parkinson’s diseases. These findings demonstrate the importance of Rho GTPases in the development, maintenance and function of the nervous system.
Appendices
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