{"id":{"repo_id":"utswmed","oai_identifier":"oai:utswmed-ir.tdl.org:2152.5/643"},"canonical_url":"https://search.dev.ndltd.org/etd/utswmed/oai:utswmed-ir.tdl.org:2152.5/643","repository":{"repo_id":"utswmed","name":"University of Texas Southwestern Medical Center","base_url":"https://utswmed-ir.tdl.org/server/oai/request"},"display":{"title":"Calcium Triggered Synaptic Vesicle Exocytosis","abstract":"Neurotransmitter release is triggered by the action potential induced influx of Ca 2+ into nerve terminals. One of the central questions in neuroscience is how Ca 2+ promotes synaptic vesicles from rest to fusion leading to release of neurotransmitters. In this thesis, I first addressed if synaptogmin-1/SNARE binding is important for synaptic vesicle release. Using two knock-in mouse lines each with single amino-acid substitution, namely D232N and D238N in synaptotagmin-1, combined with electrophysiology, I found evoked release in D232N mutant neuronal cultures is significantly increased, whereas in D238N cultures release is slightly but significantly decreased. Ca 2+ titration curves indicated the apparent Ca 2+-affinity for vesicle release significantly increased in D232N synapses. These data are consistent with biochemical studies that showed that the D232N substitution in synaptotagmin-1 increases Ca 2+-dependent SNARE bindings but leaves phospholipid binding unchanged, whereas the D238N mutant slightly decreased phospholipid binding but leaves SNARE binding insignificantly changed. Second, I addressed if synaptotamgin-2 is another Ca 2+-sensor for synaptic vesicle release. I and my colleagues used two mouse lines: one contains a single amino acid mutation in synaptotagmin-2 (I377N) and one has synaptotagmin-2 ablated from the genome. By using a combination of biophysical, biochemical and functional techniques, we determined that synaptotagmin-2 is a fast synchronous Ca 2+-sensor. Third, in collaboration with Jianyuan Sun, we explored the biophysical properties of the slow Ca 2+-sensor in the Calyx of Held. Using Ca 2+-uncaging combined with electrophysiology, we mapped increasing Ca 2+ concentrations in relation to neurotransmitter release and built a comprehensive mathematical model for the Ca 2+ control of synaptic vesicle fusion. We found compelling evidence for the existence of two Ca 2+- sensors: one (synaptotagmin-2 in the Calyx of Held) is responsible for fast synchronous release, and the other one is responsible for slow delayed synaptic release. Surprisingly, we found the two Ca 2+-sensors have similar apparent Ca 2+ affinities. This study showed clearly that synaptotagmin-2 is a fast Ca 2+-sensor, and gave us a prediction that narrows down the potential candidate for the slow Ca 2+-sensor.","abstract_html":"Neurotransmitter release is triggered by the action potential induced influx of Ca 2+ into nerve terminals. One of the central questions in neuroscience is how Ca 2+ promotes synaptic vesicles from rest to fusion leading to release of neurotransmitters. In this thesis, I first addressed if synaptogmin-1/SNARE binding is important for synaptic vesicle release. Using two knock-in mouse lines each with single amino-acid substitution, namely D232N and D238N in synaptotagmin-1, combined with electrophysiology, I found evoked release in D232N mutant neuronal cultures is significantly increased, whereas in D238N cultures release is slightly but significantly decreased. Ca 2+ titration curves indicated the apparent Ca 2+-affinity for vesicle release significantly increased in D232N synapses. These data are consistent with biochemical studies that showed that the D232N substitution in synaptotagmin-1 increases Ca 2+-dependent SNARE bindings but leaves phospholipid binding unchanged, whereas the D238N mutant slightly decreased phospholipid binding but leaves SNARE binding insignificantly changed. Second, I addressed if synaptotamgin-2 is another Ca 2+-sensor for synaptic vesicle release. I and my colleagues used two mouse lines: one contains a single amino acid mutation in synaptotagmin-2 (I377N) and one has synaptotagmin-2 ablated from the genome. By using a combination of biophysical, biochemical and functional techniques, we determined that synaptotagmin-2 is a fast synchronous Ca 2+-sensor. Third, in collaboration with Jianyuan Sun, we explored the biophysical properties of the slow Ca 2+-sensor in the Calyx of Held. Using Ca 2+-uncaging combined with electrophysiology, we mapped increasing Ca 2+ concentrations in relation to neurotransmitter release and built a comprehensive mathematical model for the Ca 2+ control of synaptic vesicle fusion. We found compelling evidence for the existence of two Ca 2+- sensors: one (synaptotagmin-2 in the Calyx of Held) is responsible for fast synchronous release, and the other one is responsible for slow delayed synaptic release. Surprisingly, we found the two Ca 2+-sensors have similar apparent Ca 2+ affinities. This study showed clearly that synaptotagmin-2 is a fast Ca 2+-sensor, and gave us a prediction that narrows down the potential candidate for the slow Ca 2+-sensor.","abstract_has_math":false,"creators":["Pang, Zhiping"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Südhof, Thomas C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-07-12T18:42:42Z","date_published":"2010-07-12T18:42:42Z","updated_at":"2026-07-24T05:52:13Z","subjects":["Calcium","Synapses","Synaptic Transmission"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["664113598"],"render_values":[{"text":"664113598","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/2152.5/643","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Südhof, Thomas C."]},{"key":"dc:creator","label":"Author","values":["Pang, Zhiping"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2010-07-12T18:42:42Z","2007-08-08"]},{"key":"dc:type","label":"Dc Type","values":["Thesis","Text","dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Calcium","Synapses","Synaptic Transmission"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2152.5/643","664113598"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Neurotransmitter release is triggered by the action potential induced influx of Ca 2+ into nerve terminals. One of the central questions in neuroscience is how Ca 2+ promotes synaptic vesicles from rest to fusion leading to release of neurotransmitters. In this thesis, I first addressed if synaptogmin-1/SNARE binding is important for synaptic vesicle release. Using two knock-in mouse lines each with single amino-acid substitution, namely D232N and D238N in synaptotagmin-1, combined with electrophysiology, I found evoked release in D232N mutant neuronal cultures is significantly increased, whereas in D238N cultures release is slightly but significantly decreased. Ca 2+ titration curves indicated the apparent Ca 2+-affinity for vesicle release significantly increased in D232N synapses. These data are consistent with biochemical studies that showed that the D232N substitution in synaptotagmin-1 increases Ca 2+-dependent SNARE bindings but leaves phospholipid binding unchanged, whereas the D238N mutant slightly decreased phospholipid binding but leaves SNARE binding insignificantly changed. Second, I addressed if synaptotamgin-2 is another Ca 2+-sensor for synaptic vesicle release. I and my colleagues used two mouse lines: one contains a single amino acid mutation in synaptotagmin-2 (I377N) and one has synaptotagmin-2 ablated from the genome. By using a combination of biophysical, biochemical and functional techniques, we determined that synaptotagmin-2 is a fast synchronous Ca 2+-sensor. Third, in collaboration with Jianyuan Sun, we explored the biophysical properties of the slow Ca 2+-sensor in the Calyx of Held. Using Ca 2+-uncaging combined with electrophysiology, we mapped increasing Ca 2+ concentrations in relation to neurotransmitter release and built a comprehensive mathematical model for the Ca 2+ control of synaptic vesicle fusion. We found compelling evidence for the existence of two Ca 2+- sensors: one (synaptotagmin-2 in the Calyx of Held) is responsible for fast synchronous release, and the other one is responsible for slow delayed synaptic release. Surprisingly, we found the two Ca 2+-sensors have similar apparent Ca 2+ affinities. This study showed clearly that synaptotagmin-2 is a fast Ca 2+-sensor, and gave us a prediction that narrows down the potential candidate for the slow Ca 2+-sensor."]},{"key":"dc:format","label":"Dc Format","values":["Electronic","application/pdf","born digital"]},{"key":"dc:title","label":"Title","values":["Calcium Triggered Synaptic Vesicle Exocytosis"]}]}],"canonical_facts":{"dc:contributor":["Südhof, Thomas C."],"dc:creator":["Pang, Zhiping"],"dc:date":["2010-07-12T18:42:42Z","2007-08-08"],"dc:description":["Neurotransmitter release is triggered by the action potential induced influx of Ca 2+ into nerve terminals. One of the central questions in neuroscience is how Ca 2+ promotes synaptic vesicles from rest to fusion leading to release of neurotransmitters. In this thesis, I first addressed if synaptogmin-1/SNARE binding is important for synaptic vesicle release. Using two knock-in mouse lines each with single amino-acid substitution, namely D232N and D238N in synaptotagmin-1, combined with electrophysiology, I found evoked release in D232N mutant neuronal cultures is significantly increased, whereas in D238N cultures release is slightly but significantly decreased. Ca 2+ titration curves indicated the apparent Ca 2+-affinity for vesicle release significantly increased in D232N synapses. These data are consistent with biochemical studies that showed that the D232N substitution in synaptotagmin-1 increases Ca 2+-dependent SNARE bindings but leaves phospholipid binding unchanged, whereas the D238N mutant slightly decreased phospholipid binding but leaves SNARE binding insignificantly changed. Second, I addressed if synaptotamgin-2 is another Ca 2+-sensor for synaptic vesicle release. I and my colleagues used two mouse lines: one contains a single amino acid mutation in synaptotagmin-2 (I377N) and one has synaptotagmin-2 ablated from the genome. By using a combination of biophysical, biochemical and functional techniques, we determined that synaptotagmin-2 is a fast synchronous Ca 2+-sensor. Third, in collaboration with Jianyuan Sun, we explored the biophysical properties of the slow Ca 2+-sensor in the Calyx of Held. Using Ca 2+-uncaging combined with electrophysiology, we mapped increasing Ca 2+ concentrations in relation to neurotransmitter release and built a comprehensive mathematical model for the Ca 2+ control of synaptic vesicle fusion. We found compelling evidence for the existence of two Ca 2+- sensors: one (synaptotagmin-2 in the Calyx of Held) is responsible for fast synchronous release, and the other one is responsible for slow delayed synaptic release. Surprisingly, we found the two Ca 2+-sensors have similar apparent Ca 2+ affinities. This study showed clearly that synaptotagmin-2 is a fast Ca 2+-sensor, and gave us a prediction that narrows down the potential candidate for the slow Ca 2+-sensor."],"dc:format":["Electronic","application/pdf","born digital"],"dc:identifier":["https://hdl.handle.net/2152.5/643","664113598"],"dc:language":["en"],"dc:subject":["Calcium","Synapses","Synaptic Transmission"],"dc:title":["Calcium Triggered Synaptic Vesicle Exocytosis"],"dc:type":["Thesis","Text","dissertation"]},"updated_at":"2026-07-24T05:52:13Z"}