ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Caspr/paranodin is an essential neuronal component of paranodal axoglial junctions, associated with contactin/F3. Its short intracellular domain contains a conserved motif (GNP motif) capable of binding protein 4.1 domains [FERM domains (four point one, ezrin, radixin, moesin)]. Schwannomin/merlin is a tumour suppressor expressed in many cell types, including in neurons, the function and partners of which are still poorly characterized. We show that the FERM domain of schwannomin binds to the paranodin GNP motif in glutathione S-transferase (GST)-pull down assays and in transfected COS-7 cells. The two proteins co-immunoprecipitated in brain extracts. In addition, paranodin and schwannomin were associated with integrin β1 in transfected cells and in brain homogenates. The presence of paranodin increased the association between integrin β1 and schwannomin or its N-terminal domain, suggesting that the interactions between these proteins are interdependent. In jimpy mutant mice, which display a severe dysmyelination with deficient paranodal junctions, the interactions between paranodin, schwannomin and integrin β1 were profoundly altered. Our results show that schwannomin and integrin β1 can be associated with paranodin in the central nervous system. Since integrin β1 and schwannomin do not appear to be enriched in paranodes they may be quantitatively minor partners of paranodin in these regions and/or be associated with paranodin at other locations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1471-4159.2003.01503.x
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