title: Localized serine protease activity and the establishment of Drosophila embryonic dorsoventral polarity.
abstract: Drosophila embryo dorsoventral polarity is established by a maternally encoded signal transduction pathway in which three sequentially acting serine proteases, Gastrulation Defective, Snake and Easter, generate the ligand that activates the Toll receptor on the ventral side of the embryo. The spatial regulation of this pathway depends upon ventrally restricted expression of the Pipe sulfotransferase in the ovarian follicle during egg formation. Several recent observations have advanced our understanding of the mechanism regulating the spatially restricted activation of Toll. First, several protein components of the vitelline membrane layer of the eggshell have been determined to be targets of Pipe-mediated sulfation. Second, the processing of Easter by Snake has been identified as the first Pipe-dependent, ventrally-restricted processing event in the pathway. Finally, Gastrulation Defective has been shown to undergo Pipe-dependent, ventral localization within the perivitelline space and to facilitate Snake-mediated processing of Easter. Together, these observations suggest that Gastrulation Defective, localized on the interior ventral surface of the eggshell in association with Pipe-sulfated eggshell proteins, recruits and mediates an interaction between Snake and Easter. This event leads to ventrally-restricted processing and activation of Easter and consequently, localized formation of the Toll ligand, and Toll activation.
authors.affiliation: Section of Molecular Cell and Developmental Biology; Institute for Cellular and Molecular Biology; University of Texas at Austin; Austin, TX USA.
authors.forename: David
authors.initials: D
authors.lastname: Stein
authors.forename: Yong Suk
authors.initials: YS
authors.lastname: Cho
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Stevens
mesh_terms: D000818:Animals; D019521:Body Patterning; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins / Q000378:metabolism*; D047108:Embryonic Development; D005260:Female; D012697:Serine Endopeptidases / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D012697:Serine Endopeptidases
keywords: Drosophila; Easter; Gastrulation Defective; Pipe; Snake; Spätzle; Toll; dorsal-ventral; follicle; perivitelline; sulfation; sulfonation
references.citation: Mech Dev. 1998 Mar;72(1-2):141-8
references.pmid: 9533958
references.citation: Dev Cell. 2003 Dec;5(6):945-50
references.pmid: 14667416
references.citation: Development. 1998 Oct;125(20):4045-53
references.pmid: 9735365
references.citation: Development. 1998 Apr;125(7):1261-7
references.pmid: 9477324
references.citation: Genetics. 1996 Aug;143(4):1653-61
references.pmid: 8844153
references.citation: Cell. 1989 Dec 22;59(6):1179-88
references.pmid: 2598266
references.citation: Cell. 1998 Nov 13;95(4):471-81
references.pmid: 9827800
references.citation: Development. 1991 Apr;111(4):1021-8
references.pmid: 1879347
references.citation: Cell. 2002 Nov 27;111(5):687-701
references.pmid: 12464180
references.citation: Cell. 1991 Jun 28;65(7):1191-201
references.pmid: 1648449
references.citation: Cell. 1991 Mar 8;64(5):961-9
references.pmid: 2001591
references.citation: Development. 2000 Dec;127(24):5541-50
references.pmid: 11076773
references.citation: Cell. 1995 Sep 8;82(5):785-94
references.pmid: 7671306
references.citation: J Biol Chem. 1999 Apr 9;274(15):10474-80
references.pmid: 10187838
references.citation: Development. 2002 Dec;129(24):5635-45
references.pmid: 12421704
references.citation: Curr Biol. 2003 Dec 2;13(23):2097-102
references.pmid: 14654000
references.citation: Mech Dev. 1998 Nov;78(1-2):113-8
references.pmid: 9858703
references.citation: Science. 1991 Oct 4;254(5028):118-22
references.pmid: 1925551
references.citation: Genes Dev. 1998 Jan 1;12(1):120-31
references.pmid: 9420336
references.citation: Nature. 1994 Apr 7;368(6471):548-51
references.pmid: 8139688
references.citation: Proc Natl Acad Sci U S A. 2000 Aug 1;97(16):9093-7
references.pmid: 10922064
references.citation: Curr Biol. 2009 Jul 28;19(14):1200-5
references.pmid: 19540119
references.citation: Cell. 1988 Jan 29;52(2):269-79
references.pmid: 2449285
references.citation: Cell. 1994 Feb 25;76(4):677-88
references.pmid: 8124709
references.citation: Science. 1987 Oct 30;238(4827):692-4
references.pmid: 3118464
references.citation: EMBO J. 2001 May 15;20(10):2387-93
references.pmid: 11350927
references.citation: Cell. 1992 Feb 7;68(3):429-40
references.pmid: 1739964
references.citation: Cell. 1989 Dec 22;59(6):1189-202
references.pmid: 2688897
references.citation: Dev Biol. 2000 Jan 15;217(2):352-61
references.pmid: 10625559
references.citation: FEBS Lett. 2010 Aug 20;584(16):3557-60
references.pmid: 20638387
references.citation: Cell. 1990 Sep 7;62(5):1019-29
references.pmid: 2203532
references.citation: Development. 1994 May;120(5):1243-50
references.pmid: 8026333
references.citation: Curr Biol. 2010 Nov 9;20(21):1953-8
references.pmid: 20970335
references.citation: Genetics. 1994 Apr;136(4):1355-65
references.pmid: 8013912
references.citation: Cell. 1989 Dec 22;59(6):1165-77
references.pmid: 2598265
references.citation: Cell. 1991 Jan 25;64(2):439-46
references.pmid: 1988156
references.citation: J Biol Chem. 1997 May 23;272(21):13980-5
references.pmid: 9153262
references.citation: Genetics. 2001 Oct;159(2):635-45
references.pmid: 11606540
references.citation: Cell. 1991 May 31;65(5):725-35
references.pmid: 1904007
references.citation: Development. 1991 Sep;113(1):35-54
references.pmid: 1765005
references.citation: EMBO Rep. 2001 Aug;2(8):721-6
references.pmid: 11493599
references.citation: Proc Natl Acad Sci U S A. 2001 Apr 24;98(9):5055-60
references.pmid: 11296245
references.citation: Curr Biol. 2010 Jun 22;20(12):1133-7
references.pmid: 20605458
references.citation: Curr Biol. 2012 Jun 5;22(11):1013-8
references.pmid: 22578419