Present address: EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
The NMDA receptor subunit NR2B of neonatal rat brain: complex formation and enrichment in axonal growth cones
Version of Record online: 25 DEC 2001
© European Neuroscience Association
European Journal of Neuroscience
Volume 10, Issue 5, pages 1553–1562, May 1998
How to Cite
Herkert, M., Röttger, S. and Becker, C.-M. (1998), The NMDA receptor subunit NR2B of neonatal rat brain: complex formation and enrichment in axonal growth cones. European Journal of Neuroscience, 10: 1553–1562. doi: 10.1046/j.1460-9568.1998.00164.x
- Issue online: 25 DEC 2001
- Version of Record online: 25 DEC 2001
- Received 23 September 1997, revised 9 December 1997, accepted 30 December 1997
- chemical cross-link;
- NR2B polypeptide;
- subcellular distribution;
The N-methyl-d-aspartate (NMDA) subtype of ionotropic glutamate receptors comprises a family of highly homologous subunits which assemble into oligomeric protein complexes. Alterations in subunit composition are developmentally regulated, leading to functionally distinct receptor populations. Here, the contribution of the subunit NR2B to NMDA receptor complex formation was analysed in neonatal rat brain, employing polyclonal antibodies raised against NR2B-specific synthetic peptides. By hydrodynamic size fractionation of the solubilized receptor protein and chemical cross-linking, NR2B antigen was found to be associated with several protein species of up to 690 kDa molecular weight. These observations show NR2B to be part of a multimeric receptor complex. Fractionation of cortex homogenates from E18 rat embryos on sucrose density gradients revealed NR2B polypeptide to be highly enriched in axonal growth cones. A similar distribution was found by fluorescence microscopy of immature hippocampal neurons, showing a preferential accumulation of NR2B antigen in axonal growth cones and varicosities. In mature cells, NR2B antigen displayed a punctated distribution pattern with redistribution to somato-dendritic spheres. The association of NR2B with axonal growth cones and processes of immature neurons suggests a role of NMDA receptors in the regulation of neurite outgrowth and migration.