Biology subjects

Wang, S. S. H.

Publications and source records attributed to Wang, S. S. H..

2 recordsLinked to original sources

bioRxiv2021

Reconstructing essential active zone functions within a synapse

Active zones are molecular machines that control neurotransmitter release through synaptic vesicle docking and priming, and through coupling of these vesicles to Ca2+ entry. The complexity of active zone machinery has made it challenging to determine which mechanisms drive these roles in release. Here, we induce RIM+ELKS knockout to eliminate active zone scaffolding networks, and then reconstruct each active zone function. Re-expression of RIM1-Zn fingers positioned Munc13 on undocked vesicles and rendered them release-competent. Reconstitution of release-triggering required docking of these vesicles to Ca2+ channels. Fusing RIM1-Zn to CaV{beta}4-subunits sufficed to restore docking, priming and release-triggering without reinstating active zone scaffolds. Hence, exocytotic activities of the 80 kDa CaV{beta}4-Zn fusion protein bypassed the need for megadalton-sized secretory machines. These data define key mechanisms of active zone function, establish that fusion competence and docking are mechanistically separable, and reveal that active zone scaffolding networks are not required for release.

neuroscience↗

bioRxiv2020

Phosphorylation triggers presynaptic phase separation of Liprin-α3 to control active zone structure

Liquid-liquid phase separation enables the assembly of membrane-less subcellular compartments, but testing its biological functions has been difficult. The presynaptic active zone, protein machinery in nerve terminals that defines sites for neurotransmitter release, may be organized through phase separation. Here, we discover that the active zone protein Liprin-3 rapidly and reversibly undergoes phase separation upon phosphorylation by PKC at a single site. RIM and Munc13 are co-recruited to membrane-attached condensates, and phospho-specific antibodies establish Liprin-3 phosphorylation in vivo. At synapses of newly generated Liprin-2/3 double knockout mice, RIM, Munc13 and the pool of releasable vesicles were reduced. Re-expression of Liprin-3 restored these defects, but mutating the Liprin-3 phosphorylation site to abolish phase condensation prevented rescue. Finally, PKC activation acutely increased RIM, Munc13 and neurotransmitter release, which depended on the presence of phosphorylatable Liprin-3. We conclude that Liprin-3 phosphorylation rapidly triggers presynaptic phase separation to modulate active zone structure and function.

neuroscience↗