PMID- 17079678 OWN - NLM STAT- MEDLINE DCOM- 20061114 LR - 20200225 IS - 1529-2401 (Electronic) IS - 0270-6474 (Print) IS - 0270-6474 (Linking) VI - 26 IP - 44 DP - 2006 Nov 1 TI - The dynamic distribution of TrkB receptors before, during, and after synapse formation between cortical neurons. PG - 11487-500 AB - Although brain-derived neurotrophic factor (BDNF) potently regulates neuronal connectivity in the developing CNS, the mechanism by which BDNF influences the formation and/or maintenance of glutamatergic synapses remains unknown. Details about the subcellular localization of the BDNF receptor, TrkB, relative to synaptic and nonsynaptic proteins on excitatory neurons should provide insight into how BDNF might exert its effects during synapse formation. Here, we investigated the subcellular localization of tyrosine kinase receptor B (TrkB) relative to synaptic vesicle-associated proteins and NMDA receptors using immunocytochemistry, confocal microscopy, and time-lapse imaging in dissociated cultures of cortical neurons before, during, and after the peak of synapse formation. We find that TrkB is present in puncta on the surface and intracellularly in both dendrites and axons throughout development. Before synapse formation, some TrkB puncta in dendrites colocalize with NMDA receptors, and almost all TrkB puncta in axons colocalize with synaptic vesicle proteins. Clusters of TrkB fused to the enhanced green fluorescent protein (TrkB-EGFP) are highly mobile in both axons and dendrites. In axons, TrkB-EGFP dynamics are almost identical to vesicle-associated protein (VAMP2-EGFP), and these proteins are often transported together. Finally, surface TrkB is found in structures that actively participate in synapse formation: axonal growth cones and dendritic filopodia. Over time, surface TrkB becomes enriched at glutamatergic synapses, which contain both catalytic and truncated TrkB. These results suggest that TrkB is in the right place at the right time to play a direct role in the formation of glutamatergic synapses between cortical neurons. FAU - Gomes, Raquel A AU - Gomes RA AD - Center for Neuroscience, University of California at Davis, Davis, California 95616, USA. FAU - Hampton, Cara AU - Hampton C FAU - El-Sabeawy, Faten AU - El-Sabeawy F FAU - Sabo, Shasta L AU - Sabo SL FAU - McAllister, A Kimberley AU - McAllister AK LA - eng GR - R01 EY013584/EY/NEI NIH HHS/United States GR - R01 EY13584/EY/NEI NIH HHS/United States PT - Comparative Study PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't PL - United States TA - J Neurosci JT - The Journal of neuroscience : the official journal of the Society for Neuroscience JID - 8102140 RN - EC 2.7.10.1 (Receptor, trkB) SB - IM MH - Animals MH - Animals, Newborn MH - Cells, Cultured MH - Cerebral Cortex/cytology/*growth & development/*metabolism MH - Neurons/cytology/*metabolism MH - Protein Transport/physiology MH - Rats MH - Receptor, trkB/*metabolism MH - Synapses/*metabolism MH - Time Factors PMC - PMC6674530 EDAT- 2006/11/03 09:00 MHDA- 2006/11/15 09:00 PMCR- 2007/05/01 CRDT- 2006/11/03 09:00 PHST- 2006/11/03 09:00 [pubmed] PHST- 2006/11/15 09:00 [medline] PHST- 2006/11/03 09:00 [entrez] PHST- 2007/05/01 00:00 [pmc-release] AID - 26/44/11487 [pii] AID - 3159907 [pii] AID - 10.1523/JNEUROSCI.2364-06.2006 [doi] PST - ppublish SO - J Neurosci. 2006 Nov 1;26(44):11487-500. doi: 10.1523/JNEUROSCI.2364-06.2006.