Brevican distinctively assembles extracellular components at the large diameter nodes of Ranvier in the CNS |
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Authors: | Yoko Bekku Uwe Rauch† Yoshifumi Ninomiya Toshitaka Oohashi |
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Institution: | Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Vessel Wall Biology, Institute for Experimental Medical Sciences, Lund University, Lund, Sweden |
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Abstract: | Brevican is known to be an abundant extracellular matrix component in the adult brain and a structural constituent of perineuronal nets. We herein show that brevican, tenascin-R (TN-R) and phosphacan are present at the nodes of Ranvier on myelinated axons with a particularly large diameter in the central nervous system. A brevican deficiency resulted in a reorganization of the nodal matrices, which was characterized by the shift of TN-R, and concomitantly phosphacan, from an axonal diameter-dependent association with nodes to an axonal diameter independent association. Supported by the co-immunoprecipitation results, these observations indicate that the presence of TN-R and phosphacan at nodes is normally brevican-dependent, while in the absence of brevican these molecules can also be recruited by versican V2. The versican V2 and Bral1 distribution was not affected, thus indicating a brevican-independent role of these two molecules for establishing hyaluronan-binding matrices at the nodes. Our results revealed that brevican plays a crucial role in determining the specialization of the hyaluronan-binding nodal matrix assemblies in large diameter nodes. |
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Keywords: | action potential extracellular matrix node of Ranvier proteoglycan scaffolding proteins tenascin-R |
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