TitleGjd2b-mediated gap junctions promote glutamatergic synapse formation and dendritic elaboration in Purkinje neurons.
Publication TypeJournal Article
Year of Publication2021
AuthorsSitaraman S, Yadav G, Agarwal V, Jabeen S, Verma S, Jadhav M, Thirumalai V
Date Published2021 Aug 04

Gap junctions between neurons serve as electrical synapses, in addition to conducting metabolites and signaling molecules. During development, early-appearing gap junctions are thought to prefigure chemical synapses, which appear much later. We present evidence for this idea at a central, glutamatergic synapse and provide some mechanistic insights. Loss or reduction in the levels of the gap junction protein Gjd2b decreased the frequency of glutamatergic miniature excitatory postsynaptic currents (mEPSCs) in cerebellar Purkinje neurons (PNs) in larval zebrafish. Ultrastructural analysis in the molecular layer showed decreased synapse density. Further, mEPSCs had faster kinetics and larger amplitudes in mutant PNs, consistent with their stunted dendritic arbors. Time-lapse microscopy in wild type and mutant PNs reveals that Gjd2b puncta promote the elongation of branches and that CaMKII may be a critical mediator of this process. These results demonstrate that Gjd2b-mediated gap junctions regulate glutamatergic synapse formation and dendritic elaboration in PNs.

Alternate JournalElife
PubMed ID34346310
Grant List500040/Z/09/Z and IA/S/17/2/503297 / / The Wellcome Trust DBT India Alliance /
BT/PR4983/MED/30/790/2012 / / Department of Biotechnology, Ministry of Science and Technology, India /
EMR/2015/000595 / / Science and Engineering Research Board /
12-R&DTFR-5.04-0800 / / Department of Atomic Energy, Government of India /
YSS/2015/000908 / / Science and Engineering Research Board /