The synaptic glycoprotein neuroplastin is involved in long-term potentiation at hippocampal CA1 synapses

K. H. Smalla, H. Matthies, K. Langnäse, S. Shabir, T. M. Böckers, U. Wyneken, S. Staak, M. Krug, P. W. Beesley, E. D. Gundelfinger

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

Abstract

Neuroplastin-65 and -55 (previously known as gp65 and gp55) are glycoproteins of the Ig superfamily that are enriched in rat forebrain synaptic membrane preparations. Whereas the two-lg domain isoform neuroplastin-55 is expressed in many tissues, the three-lg domain isoform neuroplastin-65 is brain-specific and enriched in postsynaptic density (PSD) protein preparations. Here, we have assessed the function of neuroplastin in long-term synaptic plasticity. Immunocytochemical studies with neuroplastin- 65-specific antibodies differentially stain distinct synaptic neuropil regions of the rat hippocampus with most prominent immunoreactivity in the CA1 region and the proximal molecular layer of the dentate gyrus. Kainate- induced seizures cause a significant enhancement of neuroplastin-65 association with PSDs. Similarly, long-term potentiation (LTP) of CA1 synapses in hippocampal slices enhanced the association of neuroplastin-65 with a detergent-insoluble PSD-enriched protein fraction. Several antibodies against the neuroplastins, including one specific for neuroplastin-65, inhibited the maintenance of LTP. A similar effect was observed when recombinant fusion protein containing the three extracellular lg domains of neuroplastin-65 was applied to hippocampal slices before LTP induction. Microsphere binding experiments using neuroplastin-F(c) chimeric proteins show that constructs containing lg1-3 or lg1 domains, but not lg2-3 domains mediate homophilic adhesion. These data suggest that neuroplastin plays an essential role in implementing long-term changes in synaptic activity, possibly by means of a homophilic adhesion mechanism.
Original languageAmerican English
Pages (from-to)4327-4332
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume97
Issue number8
DOIs
StatePublished - 11 Apr 2000

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