title: Neural activity selects myosin IIB and VI with a specific time window in distinct dynamin isoform-mediated synaptic vesicle reuse pathways.
abstract: Presynaptic nerve terminals must maintain stable neurotransmissions via synaptic vesicle (SV) resupply despite encountering wide fluctuations in the number and frequency of incoming action potentials (APs). However, the molecular mechanism linking variation in neural activity to SV resupply is unknown. Myosins II and VI are actin-based cytoskeletal motors that drive dendritic actin dynamics and membrane transport, respectively, at brain synapses. Here we combined genetic knockdown or molecular dysfunction and direct physiological measurement of fast synaptic transmission from paired rat superior cervical ganglion neurons in culture to show that myosins IIB and VI work individually in SV reuse pathways, having distinct dependency and time constants with physiological AP frequency. Myosin VI resupplied the readily releasable pool (RRP) with slow kinetics independently of firing rates but acted quickly within 50 ms after AP. Under high-frequency AP firing, myosin IIB resupplied the RRP with fast kinetics in a slower time window of 200 ms. Knockdown of both myosin and dynamin isoforms by mixed siRNA microinjection revealed that myosin IIB-mediated SV resupply follows amphiphysin/dynamin-1-mediated endocytosis, while myosin VI-mediated SV resupply follows dynamin-3-mediated endocytosis. Collectively, our findings show how distinct myosin isoforms work as vesicle motors in appropriate SV reuse pathways associated with specific firing patterns.
authors.affiliation: Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan and.
authors.forename: Michikata
authors.initials: M
authors.lastname: Hayashida
authors.affiliation: Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan and.
authors.forename: Shota
authors.initials: S
authors.lastname: Tanifuji
authors.affiliation: Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan and.
authors.forename: Huan
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Molecular Biology, New York State Institute for Basic Research in Developmental Disabilities, New York 10314.
authors.forename: Noriko
authors.initials: N
authors.lastname: Murakami
authors.affiliation: Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan and mochida@tokyo-med.ac.jp.
authors.forename: Sumiko
authors.identifier: http://orcid.org/0000-0001-6038-0656
authors.initials: S
authors.lastname: Mochida
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D034284:Dynamin I / Q000235:genetics / Q000378:metabolism*; D004558:Electric Stimulation; D004705:Endocytosis / Q000187:drug effects; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005260:Female; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D024501:Nonmuscle Myosin Type IIB / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D017783:Superior Cervical Ganglion / Q000166:cytology; D013572:Synaptic Vesicles / Q000378:metabolism*; D013997:Time Factors; D024723:Ventricular Myosins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D034741:RNA, Small Interfering; C075637:amphiphysin; D034284:Dynamin I; D024501:Nonmuscle Myosin Type IIB; D024723:Ventricular Myosins
keywords: action potential; dynamin; endocytosis; myosin; synaptic vesicle