Perturbations to postsynaptic glutamate receptors (GluRs) trigger retrograde signaling to precisely increase presynaptic neurotransmitter release, maintaining stable levels of synaptic strength, a process referred to as homeostatic regulation. However, the structural change of homeostatic regulation remains poorly defined.
At wild-typeDrosophilaneuromuscular junction synapse, there is one Bruchpilot (Brp) ring detected by super resolution microscopy at active zones (AZs). The research team led by Prof. ZHANG Yongqing at University of Chinese Academy of Sciences and Chinese Academy of Sciences Institute of Genetics and Developmental Biology collaborates with the research team led by JIANG Yuqiang at Center for Biomedical Imaging Research of Tsinghua University, finding that Structural Remodeling of Active Zones Is Associated with Synaptic Homeostasis. The researchers report multiple Brp rings (i.e., multipleT-bars seen by electron microscopy) at AZs of both male and female larvae when GluRs are reduced. AtGluRIIC-deficient neuromuscular junctions, quantal size was reduced but quantal content was increased, indicative of homeostatic presynaptic potentiation. Consistently, multiple Brp rings at AZs were observed in the two classic synaptic homeostasis models (i.e.,GluRIIAmutant and pharmacological blockade of GluRIIA activity). Furthermore, postsynaptic overexpression of the cell adhesion protein Neuroligin 1 partially rescued multiple Brp rings phenotype. The study thus supports that the formation of multiple Brp rings at AZs might be a structural basis for synaptic homeostasis.
The study is published on March 8 in Journal of Neuroscience entitled “Structural Remodeling of Active Zones Is Associated with Synaptic Homeostasis” (DOI:10.1523/JNEUROSCI.2002-19.2020). Dr. HONG Huilin at University of Chinese Academy of Sciences (institute: Institute of Genetics and Developmental Biology, CAS) is the first author of the paper. The study is supported by Ministry of Science and Technology of the People’s Republic of China and National Natural Science Foundation of China.
