scholarly journals EIPR1 controls dense-core vesicle cargo retention and EARP complex localization in insulin-secreting cells

2018 ◽  
Author(s):  
Irini Topalidou ◽  
Jérôme Cattin-Ortolá ◽  
Blake Hummer ◽  
Cedric S. Asensio ◽  
Michael Ailion
Keyword(s):  
Dense Core ◽  
Dense Core Vesicle ◽  
Cell Periphery ◽  
Interacting Protein ◽  
C Elegans ◽  
Insulin Secreting Cells ◽  
The Stability ◽  
Insulinoma Cells ◽  
Golgi Network

AbstractDense-core vesicles (DCVs) are secretory vesicles found in neurons and endocrine cells. DCVs package and release cargos including neuropeptides, biogenic amines, and peptide hormones. We recently identified the endosome-associated recycling protein (EARP) complex and the EARP-interacting protein EIPR-1 as proteins important for controlling levels of DCV cargos in C. elegans neurons. Here we determine the role of mammalian EIPR1 in insulinoma cells. We find that in Eipr1 KO cells, there is reduced insulin secretion, and mature DCV cargos such as insulin and carboxypeptidase E (CPE) accumulate near the trans-Golgi network and are not retained in mature DCVs in the cell periphery. In addition, we find that EIPR1 is required for the stability of the EARP complex subunits and for the localization of EARP and its association with membranes, but EIPR1 does not affect localization or function of the related Golgi-associated retrograde protein (GARP) complex. EARP is localized to two distinct compartments related to its function: an endosomal compartment and a DCV biogenesis-related compartment. We propose that EIPR1 functions with EARP to control both endocytic recycling and DCV maturation.

scholarly journals CCDC186 controls dense-core vesicle cargo sorting by exit

2019 ◽  
Author(s):  
Jérôme Cattin-Ortolá ◽  
Irini Topalidou ◽  
Ho-Tak Lau ◽  
Blake Hummer ◽  
Cedric S. Asensio ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Dense Core ◽  
Dense Core Vesicle ◽  
Cell Periphery ◽  
Golgi Retention ◽  
Entry Model ◽  
Carboxypeptidase D ◽  
Insulinoma Cells ◽  
Golgi Network ◽  
Cargo Sorting

ABSTRACTThe regulated release of peptide hormones depends on their packaging into dense-core vesicles (DCVs). Two models have been proposed for DCV cargo sorting. The “sorting by entry” model proposes that DCV cargos selectively enter nascent DCVs at the trans-Golgi network (TGN). The “sorting by exit” model proposes that sorting occurs by the post-TGN removal of non-DCV cargos and retention of mature DCV cargos. Here we show that the coiled-coil protein CCDC186 controls sorting by exit. Ccdc186 KO insulinoma cells secrete less insulin, fail to retain insulin and carboxypeptidase E in mature DCVs at the cell periphery, and fail to remove carboxypeptidase D from immature DCVs. A mutation affecting the endosome-associated recycling protein (EARP) complex causes similar defects in DCV cargo retention and removal. CCDC186 and EARP may act together to control the post-Golgi retention of cargos in mature DCVs.

scholarly journals EIPR1 controls dense-core vesicle cargo retention and EARP complex localization in insulin-secreting cells

2020 ◽  
Vol 31 (1) ◽  
pp. 59-79 ◽  
Author(s):  
Irini Topalidou ◽  
Jérôme Cattin-Ortolá ◽  
Blake Hummer ◽  
Cedric S. Asensio ◽  
Michael Ailion
Keyword(s):  
Insulin Secretion ◽  
Dense Core ◽  
Dense Core Vesicle ◽  
Secretory Vesicles ◽  
Dense Core Vesicles ◽  
Interacting Protein ◽  
Insulin Secreting Cells

Dense-core vesicles (DCVs) are secretory vesicles that package and secrete cargoes like insulin, but how cargo is sorted to DCVs is poorly understood. Here, it is shown that the EARP complex-interacting protein EIPR1 controls insulin secretion and localization of DCV cargo in insulin-secreting cells.

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

2010 ◽  
pp. no-no ◽  
Author(s):  
Mai Sato ◽  
Yasunori Mori ◽  
Takahide Matsui ◽  
Ryo Aoki ◽  
Manami Oya ◽  
...  
Keyword(s):  
Pc12 Cells ◽  
Dense Core ◽  
Dense Core Vesicle ◽  
Vesicle Exocytosis

scholarly journals BAIAP3, a C2 domain–containing Munc13 protein, controls the fate of dense-core vesicles in neuroendocrine cells

2017 ◽  
Vol 216 (7) ◽  
pp. 2151-2166 ◽  
Author(s):  
Xingmin Zhang ◽  
Shan Jiang ◽  
Kelly A. Mitok ◽  
Lingjun Li ◽  
Alan D. Attie ◽  
...  
Keyword(s):  
Neuroendocrine Cells ◽  
Dense Core ◽  
Dense Core Vesicle ◽  
Protein Homeostasis ◽  
C2 Domain ◽  
Β Cells ◽  
Calcium Dependent ◽  
Trafficking Pathway ◽  
Protein Receptor ◽  
Golgi Network

Dense-core vesicle (DCV) exocytosis is a SNARE (soluble N-ethylmaleimide–sensitive fusion attachment protein receptor)-dependent anterograde trafficking pathway that requires multiple proteins for regulation. Several C2 domain–containing proteins are known to regulate Ca2+-dependent DCV exocytosis in neuroendocrine cells. In this study, we identified others by screening all (∼139) human C2 domain–containing proteins by RNA interference in neuroendocrine cells. 40 genes were identified, including several encoding proteins with known roles (CAPS [calcium-dependent activator protein for secretion 1], Munc13-2, RIM1, and SYT10) and many with unknown roles. One of the latter, BAIAP3, is a secretory cell–specific Munc13-4 paralog of unknown function. BAIAP3 knockdown caused accumulation of fusion-incompetent DCVs in BON neuroendocrine cells and lysosomal degradation (crinophagy) of insulin-containing DCVs in INS-1 β cells. BAIAP3 localized to endosomes was required for Golgi trans-Golgi network 46 (TGN46) recycling, exhibited Ca2+-stimulated interactions with TGN SNAREs, and underwent Ca2+-stimulated TGN recruitment. Thus, unlike other Munc13 proteins, BAIAP3 functions indirectly in DCV exocytosis by affecting DCV maturation through its role in DCV protein recycling. Ca2+ rises that stimulate DCV exocytosis may stimulate BAIAP3-dependent retrograde trafficking to maintain DCV protein homeostasis and DCV function.

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

Traffic ◽  
2004 ◽  
Vol 5 (7) ◽  
pp. 544-559 ◽  
Author(s):  
Tobias R. Zahn ◽  
Joseph K. Angleson ◽  
Margaret A. MacMorris ◽  
Erin Domke ◽  
John F. Hutton ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Dense Core ◽  
Dense Core Vesicle ◽  
Vesicle Dynamics

scholarly journals Dynamics of Immature Secretory Granules: Role of Cytoskeletal Elements during Transport, Cortical Restriction, and F-Actin-dependent Tethering

2001 ◽  
Vol 12 (5) ◽  
pp. 1353-1365 ◽  
Author(s):  
Rüdiger Rudolf ◽  
Thorsten Salm ◽  
Amin Rustom ◽  
Hans-Hermann Gerdes
Keyword(s):  
Secretory Granules ◽  
Late Phase ◽  
Cell Cortex ◽  
Cell Periphery ◽  
Dependent Manner ◽  
Chromogranin B ◽  
Cooperative Action ◽  
Cytoskeletal Elements ◽  
Golgi Network

Secretory granules store neuropeptides and hormones and exhibit regulated exocytosis upon appropriate cellular stimulation. They are generated in the trans-Golgi network as immature secretory granules, short-lived vesicular intermediates, which undergo a complex and poorly understood maturation process. Due to their short half-life and low abundance, real-time studies of immature secretory granules have not been previously possible. We describe here a pulse/chase-like system based on the expression of a human chromogranin B-GFP fusion protein in neuroendocrine PC12 cells, which permits direct visualization of the budding of immature secretory granules and their dynamics during maturation. Live cell imaging revealed that newly formed immature secretory granules are transported in a direct and microtubule-dependent manner within a few seconds to the cell periphery. Our data suggest that the cooperative action of microtubules and actin filaments restricts immature secretory granules to the F-actin-rich cell cortex, where they move randomly and mature completely within a few hours. During this maturation period, secretory granules segregate into pools of different motility. In a late phase of maturation, 60% of secretory granules were found to be immobile and about half of these underwent F-actin-dependent tethering.

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

2011 ◽  
Vol 22 (21) ◽  
pp. 4134-4149 ◽  
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.

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

2009 ◽  
Vol 186 (6) ◽  
pp. 897-914 ◽  
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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