title: Polarized exocyst-mediated vesicle fusion directs intracellular lumenogenesis within the C. elegans excretory cell.
abstract: Lumenogenesis of small seamless tubes occurs through intracellular membrane growth and directed vesicle fusion events. Within the Caenorhabditis elegans excretory cell, which forms seamless intracellular tubes (canals) that mediate osmoregulation, lumens grow in length and diameter when vesicles fuse with the expanding lumenal surface. Here, we show that lumenal vesicle fusion depends on the small GTPase RAL-1, which localizes to vesicles and acts through the exocyst vesicle-tethering complex. Loss of either the exocyst or RAL-1 prevents excretory canal lumen extension. Within the excretory canal and other polarized cells, the exocyst co-localizes with the PAR polarity proteins PAR-3, PAR-6 and PKC-3. Using early embryonic cells to determine the functional relationships between the exocyst and PAR proteins, we show that RAL-1 recruits the exocyst to the membrane, while PAR proteins concentrate membrane-localized exocyst proteins to a polarized domain. These findings reveal that RAL-1 and the exocyst direct the polarized vesicle fusion events required for intracellular lumenogenesis of the excretory cell, suggesting mechanistic similarities in the formation of topologically distinct multicellular and intracellular lumens.
authors.affiliation: Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA; Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Armenti
authors.affiliation: Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA; Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Chan
authors.affiliation: Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA; Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA. Electronic address: Jeremy.Nance@med.nyu.edu.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Nance
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology*; D064587:Osmoregulation / Q000235:genetics; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D034622:RNA Interference; D034741:RNA, Small Interfering; D022142:Secretory Vesicles / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics; D020725:ral GTP-Binding Proteins / Q000235:genetics*
chemical_list: D029742:Caenorhabditis elegans Proteins; D034741:RNA, Small Interfering; D033921:Vesicular Transport Proteins; C512642:par-6 protein, C elegans; C097238:PAR-3 protein, C elegans; D017346:Protein Serine-Threonine Kinases; C115015:PKC-3 protein; D011493:Protein Kinase C; D020725:ral GTP-Binding Proteins
keywords: Exocyst; Lumenogenesis; Osmoregulation; PAR proteins; Tubulogenesis; Vesicle trafficking
references.citation: Nat Cell Biol. 2013 Feb;15(2):157-68
references.pmid: 23334499
references.citation: Nat Methods. 2012 Jan 30;9(2):117-8
references.pmid: 22290181
references.citation: Int J Biochem Cell Biol. 2006;38(11):1841-7
references.pmid: 16781882
references.citation: Development. 2011 Mar;138(5):799-809
references.pmid: 21303844
references.citation: Development. 2006 Sep;133(18):3507-16
references.pmid: 16899536
references.citation: Mol Biol Cell. 2009 May;20(10):2522-9
references.pmid: 19297529
references.citation: Science. 2008 Jun 27;320(5884):1771-4
references.pmid: 18583611
references.citation: Cell. 2012 Jul 6;150(1):65-77
references.pmid: 22738726
references.citation: Dev Cell. 2004 Jun;6(6):865-73
references.pmid: 15177034
references.citation: J Cell Biol. 2005 Sep 26;170(7):1029-37
references.pmid: 16186252
references.citation: PLoS One. 2009;4(3):e4625
references.pmid: 19259264
references.citation: Development. 1998 Sep;125(18):3607-14
references.pmid: 9716526
references.citation: Development. 2013 Jul;140(14):2985-96
references.pmid: 23760958
references.citation: Exp Cell Res. 1996 Apr 10;224(1):39-51
references.pmid: 8612690
references.citation: Dev Biol. 2014 Jun 1;390(1):41-50
references.pmid: 24607370
references.citation: Genetics. 1998 Jul;149(3):1323-34
references.pmid: 9649523
references.citation: Curr Biol. 2011 Nov 22;21(22):1942-8
references.pmid: 22079115
references.citation: Genetics. 2001 Mar;157(3):1217-26
references.pmid: 11238406
references.citation: Mol Cell. 2000 Aug;6(2):445-55
references.pmid: 10983990
references.citation: Cell. 2010 May 28;141(5):757-74
references.pmid: 20510924
references.citation: Curr Biol. 2010 Feb 23;20(4):359-66
references.pmid: 20137948
references.citation: Nat Cell Biol. 2006 Mar;8(3):227-37
references.pmid: 16474385
references.citation: J Biol Chem. 1996 Aug 16;271(33):19710-6
references.pmid: 8702675
references.citation: Nature. 2003 Aug 7;424(6949):685-9
references.pmid: 12894212
references.citation: J Cell Biol. 2004 Dec 6;167(5):889-901
references.pmid: 15583031
references.citation: Development. 2007 Apr;134(7):1259-68
references.pmid: 17314130
references.citation: Nat Cell Biol. 2013 Feb;15(2):143-56
references.pmid: 23334498
references.citation: Nat Cell Biol. 2010 Nov;12(11):1035-45
references.pmid: 20890297
references.citation: Nat Cell Biol. 2002 Jan;4(1):73-8
references.pmid: 11744922
references.citation: BMC Dev Biol. 2008 Dec 30;8:119
references.pmid: 19116030
references.citation: Nat Genet. 2008 Nov;40(11):1375-83
references.pmid: 18953339
references.citation: Development. 2003 Nov;130(22):5339-50
references.pmid: 13129846
references.citation: G3 (Bethesda). 2014 Jan 10;4(1):173-83
references.pmid: 24192838
references.citation: EMBO J. 2007 Dec 12;26(24):5083-92
references.pmid: 17989692
references.citation: Dev Cell. 2009 Feb;16(2):222-31
references.pmid: 19217424
references.citation: J Struct Biol. 2005 Oct;152(1):36-51
references.pmid: 16182563
references.citation: EMBO J. 1991 Dec;10(12):3959-70
references.pmid: 1935914
references.citation: J Biol Chem. 2003 Dec 19;278(51):51743-8
references.pmid: 14525976
references.citation: Nat Cell Biol. 2013 Jan;15(1):103-12
references.pmid: 23242217
references.citation: Gene. 2001 Jan 24;263(1-2):103-12
references.pmid: 11223248
references.citation: Nat Cell Biol. 2002 Jan;4(1):66-72
references.pmid: 11740492
references.citation: J Cell Sci. 2013 Apr 1;126(Pt 7):1692-702
references.pmid: 23424200
references.citation: PLoS Genet. 2009 Jul;5(7):e1000553
references.pmid: 19668342
references.citation: J Cell Sci. 2014 Feb 1;127(Pt 3):686-99
references.pmid: 24284074
references.citation: Curr Opin Cell Biol. 2009 Aug;21(4):537-42
references.pmid: 19473826
references.citation: Genetics. 2011 Sep;189(1):153-64
references.pmid: 21750259
references.citation: PLoS Biol. 2009 Nov;7(11):e1000235
references.pmid: 19885391
references.citation: Curr Biol. 2001 Oct 2;11(19):1492-502
references.pmid: 11591316
references.citation: J Biol Chem. 2011 Jun 24;286(25):22469-77
references.pmid: 21543338
references.citation: J Cell Sci. 2009 May 15;122(Pt 10):1499-506
references.pmid: 19383721
references.citation: Protoplasma. 2012 Jul;249(3):587-97
references.pmid: 21997494
references.citation: J Ultrastruct Res. 1983 Feb;82(2):156-71
references.pmid: 6827646
references.citation: Dev Biol. 1999 Oct 1;214(1):227-41
references.pmid: 10491271
references.citation: J Biol Chem. 2005 Nov 18;280(46):38787-94
references.pmid: 16159881
references.citation: Nat Cell Biol. 2005 Mar;7(3):262-9
references.pmid: 15723052
references.citation: Nat Methods. 2009 May;6(5):343-5
references.pmid: 19363495
references.citation: Mol Biol Cell. 2000 Dec;11(12):4259-75
references.pmid: 11102522
references.citation: J Struct Biol. 1996 Jan-Feb;116(1):71-6
references.pmid: 8742726
references.citation: Dev Biol. 2010 May 1;341(1):34-55
references.pmid: 19778532
references.citation: Development. 2012 Mar;139(5):979-90
references.pmid: 22278925
references.citation: J Exp Zool. 1984 Jul;231(1):45-56
references.pmid: 6470649
references.citation: Nat Cell Biol. 2012 Mar 11;14(4):386-93
references.pmid: 22407366
references.citation: J Biol Chem. 2001 Aug 10;276(32):29792-7
references.pmid: 11406615
references.citation: Development. 2010 Jun;137(11):1833-42
references.pmid: 20431121