title: PKA activation bypasses the requirement for UNC-31 in the docking of dense core vesicles from C. elegans neurons.
abstract: The nematode C. elegans provides a powerful model system for exploring the molecular basis of synaptogenesis and neurotransmission. However, the lack of direct functional assays of release processes has largely prevented an in depth understanding of the mechanism of vesicular exocytosis and endocytosis in C. elegans. We address this technical limitation by developing direct electrophysiological assays, including membrane capacitance and amperometry measurements, in primary cultured C. elegans neurons. In addition, we have succeeded in monitoring the docking and fusion of single dense core vesicles (DCVs) employing total internal reflection fluorescence microscopy. With these approaches and mutant perturbation analysis, we provide direct evidence that UNC-31 is required for the docking of DCVs at the plasma membrane. Interestingly, the defect in DCV docking caused by UNC-31 mutation can be fully rescued by PKA activation. We also demonstrate that UNC-31 is required for UNC-13-mediated augmentation of DCV exocytosis.
authors.affiliation: Key Laboratory of Molecular Biophysics, Ministry of Education, and Joint Laboratory of Institute of Biophysics, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Ke-Ming
authors.initials: KM
authors.lastname: Zhou
authors.forename: Yong-Ming
authors.initials: YM
authors.lastname: Dong
authors.forename: Qian
authors.initials: Q
authors.lastname: Ge
authors.forename: Dan
authors.initials: D
authors.lastname: Zhu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Xian-Guang
authors.initials: XG
authors.lastname: Lin
authors.forename: Tao
authors.initials: T
authors.lastname: Liang
authors.forename: Zheng-Xing
authors.initials: ZX
authors.lastname: Wu
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism* / Q000648:ultrastructure; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D005089:Exocytosis / Q000502:physiology; D049452:Green Fluorescent Proteins; D007425:Intracellular Membranes / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D009420:Nervous System / Q000378:metabolism* / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D009489:Neurosecretion / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D012701:Serotonin / Q000378:metabolism; D013570:Synaptic Membranes / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D029742:Caenorhabditis elegans Proteins; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018377:Neurotransmitter Agents; C107581:UNC-31 protein, C elegans; C083141:phorbol ester binding protein; D049452:Green Fluorescent Proteins; D012701:Serotonin; D017868:Cyclic AMP-Dependent Protein Kinases