The vacuolar ATPase is required for physiological as well as pathological activation of the Notch receptor.
Evidence indicates that endosomal entry promotes signaling by the Notch receptor, but the mechanisms involved are not clear. In a search for factors that regulate Notch activation in endosomes, we isolated mutants in Drosophila genes that encode subunits of the vacuolar ATPase (V-ATPase) proton pump. Cells lacking V-ATPase function display impaired acidification of the endosomal compartment and a correlated failure to degrade endocytic cargoes. V-ATPase mutant cells internalize Notch and accumulate it in the lysosome, but surprisingly also show a substantial loss of both physiological and ectopic Notch activation in endosomes. V-ATPase activity is required in signal-receiving cells for Notch signaling downstream of ligand activation but upstream of gamma-secretase-dependent S3 cleavage. These data indicate that V-ATPase, probably via acidification of early endosomes, promotes not only the degradation of Notch in the lysosome but also the activation of Notch signaling in endosomes. The results also suggest that the ionic properties of the endosomal lumen might regulate Notch cleavage, providing a rationale for physiological as well as pathological endocytic control of Notch activity.
Vaccari
Thomas
T
Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA. thomas.vaccari@ifom-ieo-campus.it
Duchi
Serena
S
Cortese
Katia
K
Tacchetti
Carlo
C
Bilder
David
D
D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D005123:Eye / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D017344:Genes, Insect; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; C497759:N protein, Drosophila; D051880:Receptors, Notch; D025262:Vacuolar Proton-Translocating ATPases
J Cell Biol. 2009 Mar 9;184(5):621-9
19255248
Curr Mol Med. 2006 Dec;6(8):905-18
17168741
Mol Biol Cell. 2009 Mar;20(6):1705-14
19158398
Mol Cell Biol. 2008 Jan;28(1):165-76
17967888
Dev Biol. 1999 Sep 1;213(1):33-53
10452845
Dev Cell. 2005 Nov;9(5):687-98
16256743
J Cell Sci. 2009 Jul 15;122(Pt 14):2413-23
19571114
Physiol Genomics. 2005 Jul 14;22(2):128-38
15855386
Development. 2005 Oct;132(19):4299-308
16141223
Mol Cell. 1999 Oct;4(4):479-86
10549280
Development. 2000 Feb;127(4):851-60
10648243
Br J Cancer. 2009 Jun 16;100(12):1957-65
19455146
Nat Cell Biol. 2006 Feb;8(2):124-36
16415858
J Biol Chem. 2003 Jul 18;278(29):26687-94
12736250
Curr Biol. 2004 Feb 3;14(3):R129-38
14986688
Genetics. 2007 Nov;177(3):1667-77
17947427
Exp Cell Res. 2009 May 15;315(9):1549-55
18845146
Science. 2000 Jul 7;289(5476):113-6
10884224
Cell. 2001 May 4;105(3):345-55
11348591
Cell. 2008 May 30;133(5):852-63
18510929
Traffic. 2009 Jul;10(7):792-802
19416471
Mol Biol Cell. 2006 Sep;17(9):3989-4001
16837550
Br J Cancer. 2009 Jun 16;100(12):1879-88
19513078
Acta Crystallogr D Biol Crystallogr. 2006 May;62(Pt 5):483-8
16627940
Curr Opin Genet Dev. 2007 Feb;17(1):52-9
17178457
Development. 2001 Dec;128(23):4737-46
11731454
Nat Rev Mol Cell Biol. 2002 Feb;3(2):94-103
11836511
Dev Cell. 2009 Sep;17(3):387-402
19758563
Genes Dev. 2001 Jun 1;15(11):1393-405
11390359
J Biol Chem. 2006 Mar 17;281(11):7294-301
16361256
Dev Cell. 2007 Mar;12(3):431-42
17336908
J Cell Biol. 2008 Feb 25;180(4):755-62
18299346
Cell. 2002 Jan 25;108(2):261-9
11832215
Nat Cell Biol. 2005 Dec;7(12):1232-9
16258546
J Biol Chem. 1996 Nov 29;271(48):30677-84
8940044
Neurobiol Dis. 2007 Mar;25(3):686-96
17207630
Curr Opin Genet Dev. 2009 Aug;19(4):323-8
19447603