Shigeki Watanabe, Ph.D.
University of Utah & Charité Universitätsmedizin Berlin
Shigeki Watanabe received his undergraduate and Ph.D. degrees from the University of Utah. Under the mentorship of Dr. Erik Jorgensen, he carried out ultrastructural characterizations of Caenorhabditis elegans neuromuscular junctions and developed two novel techniques in electron microscopy that allow visualization of proteins and membrane movements within synapses at extremely high temporal resolution. For his postdoctoral work with Dr. Christian Rosenmund, he applied these novel techniques to mouse hippocampal neurons and studied how synaptic vesicles are consumed and recycled at mammalian central synapses. He is starting his own lab at Johns Hopkins University where his research will focus on understanding the mechanisms underlying the rapid reorganization of membrane, proteins, and organelles that mediate synaptic plasticity.
Slow or Fast? – A Tale of Synaptic Vesicle Recycling
Speed is a critical factor at synapses. To sustain synaptic transmission, synaptic vesicles must be reconstituted rapidly at synapses. To elucidate the mechanisms underlying synaptic vesicle recycling, Shigeki Watanabe combined optogenetic stimulation of neurons with high-pressure freezing and captured dynamic membrane movements in electron micrographs with a millisecond temporal resolution. He discovered a novel form of clathrin-independent endocytosis, now termed ‘ultrafast endocytosis’, that retrieves vesicles from the plasma membrane immediately after vesicle fusion. Dr. Watanabe has further demonstrated that endocytic vesicles are delivered to a synaptic endosome, from which clathrin regenerates synaptic vesicles. These results indicate that the immediate role for endocytosis is perhaps not to recover synaptic vesicles, but rather to clear the fusion site so that another vesicle can fuse in rapid succession. The discovery of this recycling pathway will advance our understanding of the cellular and molecular underpinnings of the vesicle cycle at synapses.
For Dr. Watanabe’s full essay, see Science online at sciencemag.org.