| Autor: |
Oleszewski, Matthias, Beer, Sandra, Katich, Stephanie, Geiger, Claudia, Zeller, Yvonka, Altevogt, Peter, Rauch, Uwe |
| Zdroj: |
Journal of Biological Chemistry; August 1999, Vol. 274 Issue: 35 p24602-24610, 9p |
| Abstrakt: |
The cell adhesion molecule L1, a 200–220-kDa type I membrane glycoprotein of the Ig superfamily, mediates many neuronal processes. Originally studied in the nervous system, L1 is expressed by hematopoietic and many epithelial cells, suggesting a more expanded role. L1 supports homophilic L1-L1 and integrin-mediated cell binding and can also bind with high affinity to the neural proteoglycan neurocan; however, the binding site is unknown. We have dissected the L1 molecule and investigated the cell binding ability of Ig domains 1 and 6. We report that RGD sites in domain 6 support α5β1- or αvβ3-mediated integrin binding and that both RGD sites are essential. Cooperation of RGD sites with neighboring domains are necessary for α5β1. A T cell hybridoma and activated T cells could bind to L1 in the absence of RGDs. This binding was supported by Ig domain 1 and mediated by cell surface-exposed neurocan. Lymphoid and brain-derived neurocan were structurally similar. We also present evidence that a fusion protein of the Ig 1-like domain of L1 can bind to recombinant neurocan. Our results support the notion that L1 provides distinct cell binding sites that may serve in cell-cell or cell-matrix interactions. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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