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CLIP-170 : Interaction avec LIS1, régulations et implication dans le fonctionnement du complexe dynéine/dynactine.

Abstract : CLIP-170 (Cytoplasmic Linker Protein of 170 kDa) links endosomes to MTs in vitro. It also treadmills at microtubule (MT) plus ends and it is involved in the regulation of MT dynamics in vivo. CLIP-170 has been proposed to mediate MTs interactions with cortical cues and kinetochores. Furthermore, it is thought to mediate the association of dynein/dynactin motor complex to MT plus ends, and it is also known to bind kinetochores in a dynein/dynactin-dependent way, both via its C-terminal domain which contains two zinc finger motifs.
Here we demonstrate colocalization and direct interaction between CLIP-170 and LIS1, a protein implicated in brain development and known to interact directly with dynein and dynactin. We provide evidence that, in mammalian cells, LIS1 recruitment to kinetochores is dynein/dynactin dependent, and recruitment of CLIP-170 on these structures is dependent on its binding site to LIS1, located in the distal zinc finger motif. We found also that LIS1 localizes at growing MT plus ends in a CLIP-170 dependent way. Overexpression of CLIP-170 results in a zinc finger dependent localization of a phospho-LIS1 isoform and dynactin to MT bundles, raising the possibility that CLIP-170 and LIS1 regulate dynein/dynactin binding to MTs. This work suggests that LIS1 is a regulated adapter between CLIP-170 and cytoplasmic dynein.
We studied different point mutations in LIS1 found in Lissencephaly patients. We demonstrated that these point mutations affect protein stability, albeit at different levels, affect folding and in addition the mutated proteins do not properly localize in cells. Protein-protein interactions were also altered with some differences among the mutated proteins. Overall, one single assay is not sufficient to predict the lissencephaly phenotype. However, the averaged sum of the assays results translated to numerical values yielded a correlative phenotypic prediction. Moreover, we mapped domains within LIS1 involved in interaction with MTs.
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https://tel.archives-ouvertes.fr/tel-00344719
Contributor : Frédéric Coquelle <>
Submitted on : Friday, December 5, 2008 - 3:14:54 PM
Last modification on : Friday, October 23, 2020 - 4:42:02 PM
Long-term archiving on: : Monday, June 7, 2010 - 10:25:34 PM

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  • HAL Id : tel-00344719, version 1

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Frédéric Coquelle. CLIP-170 : Interaction avec LIS1, régulations et implication dans le fonctionnement du complexe dynéine/dynactine.. Biologie cellulaire. Université Paris Sud - Paris XI, 2003. Français. ⟨tel-00344719⟩

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