Dishevelled interacts with the DIX domain polymerization interface of Axin to interfere with its function in down-regulating β-catenin.
Wnt/β-catenin signaling controls numerous steps in normal animal development and can also cause cancer if inappropriately activated. In the absence of Wnt, β-catenin is targeted continuously for proteasomal degradation by the Axin destruction complex, whose activity is blocked upon Wnt stimulation by Dishevelled, which recruits Axin to the plasma membrane and assembles it into a signalosome. This key event during Wnt signal transduction depends on dynamic head-to-tail polymerization by the DIX domain of Dishevelled. Here, we use rescue assays in Drosophila tissues and functional assays in human cells to show that polymerization-blocking mutations in the DIX domain of Axin disable its effector function in down-regulating Armadillo/β-catenin and its response to Dishevelled during Wnt signaling. Intriguingly, NMR spectroscopy revealed that the purified DIX domains of the two proteins interact with each other directly through their polymerization interfaces, whereby the same residues mediate both homo- and heterotypic interactions. This result implies that Dishevelled has the potential to act as a "natural" dominant-negative, binding to the polymerization interface of Axin's DIX domain to interfere with its self-assembly, thereby blocking its effector function.
Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.
Marc
M
Fiedler
Carolina
C
Mendoza-Topaz
Trevor J
TJ
Rutherford
Juliusz
J
Mieszczanek
Mariann
M
Bienz
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D060466:Axin Protein; D001704:Biopolymers / Q000378:metabolism*; D000072261:Dishevelled Proteins; D015536:Down-Regulation; D004330:Drosophila; D029721:Drosophila Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010750:Phosphoproteins / Q000378:metabolism*; D017354:Point Mutation; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D051176:beta Catenin / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D060466:Axin Protein; C118000:Axn protein, Drosophila; D001704:Biopolymers; D000072261:Dishevelled Proteins; D029721:Drosophila Proteins; D010750:Phosphoproteins; D051176:beta Catenin; C000606588:dsh protein, Drosophila
J Biol Chem. 1999 Feb 5;274(6):3439-45
9920888
Dev Biol. 2008 Aug 1;320(1):226-41
18561909
Dev Cell. 2009 Jul;17(1):9-26
19619488
Science. 1998 Apr 24;280(5363):596-9
9554852
PLoS One. 2009;4(3):e4926
19293931
J Biol Chem. 2004 Sep 17;279(38):39366-73
15262978
J Biol Chem. 1999 May 14;274(20):14090-3
10318824
J Biol Chem. 2006 Jan 13;281(2):1027-38
16293619
EMBO J. 1998 Mar 2;17(5):1371-84
9482734
Curr Biol. 2003 May 27;13(11):960-6
12781135
PLoS One. 2008;3(12):e4046
19107203
Nat Struct Mol Biol. 2007 Jun;14(6):484-92
17529994
Science. 1999 Mar 12;283(5408):1739-42
10073940
BMC Syst Biol. 2010 May 06;4:57
20459599
Nature. 2002 Oct 17;419(6908):726-9
12384700
Cell. 2006 Nov 3;127(3):469-80
17081971
Development. 2002 Jun;129(11):2565-76
12015286
Curr Biol. 2007 Mar 20;17(6):556-61
17320388
J Cell Sci. 2010 May 1;123(Pt 9):1588-99
20388731
Science. 1997 Mar 21;275(5307):1787-90
9065402
Genetics. 2003 Apr;163(4):1427-38
12702686
Curr Biol. 1998 May 7;8(10):573-81
9601641
J Biol Chem. 2005 Feb 11;280(6):5054-60
15579909
Structure. 2001 Dec;9(12):1143-52
11738041
J Cell Sci. 2005 Nov 15;118(Pt 22):5269-77
16263762
BMB Rep. 2010 Sep;43(9):609-13
20846493
EMBO J. 2003 Feb 3;22(3):494-501
12554650
Mol Cell Biol. 1999 Jun;19(6):4414-22
10330181
Cell. 2000 Aug 4;102(3):349-62
10975525
EMBO J. 1999 May 17;18(10):2823-35
10329628
J Cell Sci. 2007 Jul 15;120(Pt 14):2402-12
17606995
J Magn Reson B. 1995 Jul;108(1):94-8
7627436
Science. 2007 Jun 15;316(5831):1619-22
17569865
Development. 2008 Jan;135(2):367-75
18077588
PLoS Biol. 2003 Oct;1(1):E10
14551908
Curr Biol. 1998 May 7;8(10):591-4
9601644