Dense Core Vesicle Dynamics in Caenorhabditis elegans Neurons and the Role of Kinesin UNC-104

Despite a key role for dense core vesicles (DCVs) in neuronal function, there are major gaps in our understanding of DCV biogenesis. A genetic screen for Caenorhabditis elegans mutants with behavioral defects consistent with impaired DCV function yielded five mutations in UNC-108 (Rab2). A genetic analysis showed that unc-108 mutations impair a DCV function unrelated to neuropeptide release that, together with neuropeptide release, fully accounts for the role of DCVs in locomotion. An electron microscopy analysis of DCVs in unc-108 mutants, coupled with quantitative imaging of DCV cargo proteins, revealed that Rab2 acts in cell somas during DCV maturation to prevent the loss of soluble and membrane cargo. In Rab2 null mutants, two thirds of these cargoes move to early endosomes via a PI(3)P-dependent trafficking pathway, whereas aggregated neuropeptides are unaffected. These results reveal how neurons solve a challenging trafficking problem using the most highly conserved animal Rab.

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Role of the polybasic sequence in the Doc2α C2B domain in dense-core vesicle exocytosis in PC12 cells

Journal of Neurochemistry ◽

10.1111/j.1471-4159.2010.06739.x ◽

2010 ◽

pp. no-no ◽

Cited By ~ 4

Author(s):

Mai Sato ◽

Yasunori Mori ◽

Takahide Matsui ◽

Ryo Aoki ◽

Manami Oya ◽

...

Keyword(s):

Pc12 Cells ◽

Dense Core ◽

Dense Core Vesicle ◽

Vesicle Exocytosis

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The functional role of CAPS family proteins in dense-core vesicle trafficking

Neuroscience Research ◽

10.1016/j.neures.2009.09.050 ◽

2009 ◽

Vol 65 ◽

pp. S42

Author(s):

Tetsushi Sadakata ◽

Teiichi Furuichi

Keyword(s):

Functional Role ◽

Vesicle Trafficking ◽

Dense Core ◽

Dense Core Vesicle

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Munc18-1 domain-1 controls vesicle docking and secretion by interacting with syntaxin-1 and chaperoning it to the plasma membrane

Molecular Biology of the Cell ◽

10.1091/mbc.e11-02-0135 ◽

2011 ◽

Vol 22 (21) ◽

pp. 4134-4149 ◽

Cited By ~ 31

Author(s):

Gayoung A. Han ◽

Nancy T. Malintan ◽

Ner Mu Nar Saw ◽

Lijun Li ◽

Liping Han ◽

...

Keyword(s):

Molecular Chaperone ◽

Dense Core ◽

Dense Core Vesicle ◽

Attachment Protein ◽

Vesicle Docking ◽

Protein Receptor ◽

Sensitive Factor ◽

Intracellular Expression ◽

Factor Attachment Protein Receptor

Munc18-1 plays pleiotropic roles in neurosecretion by acting as 1) a molecular chaperone of syntaxin-1, 2) a mediator of dense-core vesicle docking, and 3) a priming factor for soluble N-ethylmaleimide–sensitive factor attachment protein receptor–mediated membrane fusion. However, how these functions are executed and whether they are correlated remains unclear. Here we analyzed the role of the domain-1 cleft of Munc18-1 by measuring the abilities of various mutants (D34N, D34N/M38V, K46E, E59K, K46E/E59K, K63E, and E66A) to bind and chaperone syntaxin-1 and to restore the docking and secretion of dense-core vesicles in Munc18-1/-2 double-knockdown cells. We identified striking correlations between the abilities of these mutants to bind and chaperone syntaxin-1 with their ability to restore vesicle docking and secretion. These results suggest that the domain-1 cleft of Munc18-1 is essential for binding to syntaxin-1 and thereby critical for its chaperoning, docking, and secretory functions. Our results demonstrate that the effect of the alleged priming mutants (E59K, D34N/M38V) on exocytosis can largely be explained by their reduced syntaxin-1–chaperoning functions. Finally, our data suggest that the intracellular expression and distribution of syntaxin-1 determines the level of dense-core vesicle docking.

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UNC-108/RAB-2 and its effector RIC-19 are involved in dense core vesicle maturation in Caenorhabditis elegans

The Journal of Cell Biology ◽

10.1083/jcb.200902096 ◽

2009 ◽

Vol 186 (6) ◽

pp. 897-914 ◽

Cited By ~ 67

Author(s):

Marija Sumakovic ◽

Jan Hegermann ◽

Ling Luo ◽

Steven J. Husson ◽

Katrin Schwarze ◽

...

Keyword(s):

Nervous System ◽

Caenorhabditis Elegans ◽

Vesicular Trafficking ◽

Dense Core ◽

Dense Core Vesicle ◽

Vesicle Release ◽

C Elegans ◽

Golgi Membranes ◽

Human Diabetes ◽

Synaptic Vesicle Release

Small guanosine triphosphatases of the Rab family regulate intracellular vesicular trafficking. Rab2 is highly expressed in the nervous system, yet its function in neurons is unknown. In Caenorhabditis elegans, unc-108/rab-2 mutants have been isolated based on their locomotory defects. We show that the locomotion defects of rab-2 mutants are not caused by defects in synaptic vesicle release but by defects in dense core vesicle (DCV) signaling. DCVs in rab-2 mutants are often enlarged and heterogeneous in size; however, their number and distribution are not affected. This implicates Rab2 in the biogenesis of DCVs at the Golgi complex. We demonstrate that Rab2 is required to prevent DCV cargo from inappropriately entering late endosomal compartments during DCV maturation. Finally, we show that RIC-19, the C. elegans orthologue of the human diabetes autoantigen ICA69, is also involved in DCV maturation and is recruited to Golgi membranes by activated RAB-2. Thus, we propose that RAB-2 and its effector RIC-19 are required for neuronal DCV maturation.

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