| Structural highlights
Function
[ARHG4_HUMAN] Acts as guanine nucleotide exchange factor (GEF) for RHOA, RAC1 and CDC42 GTPases. Binding of APC may activate RAC1 GEF activity. The APC-ARHGEF4 complex seems to be involved in cell migration as well as in E-cadherin-mediated cell-cell adhesion. Required for MMP9 up-regulation via the JNK signaling pathway in colorectal tumor cells. Involved in tumor angiogenesis and may play a role in intestinal adenoma formation and tumor progression.[1] [2] [3] [4] [5]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Autoinhibition of the Rho guanine nucleotide exchange factor ASEF is relieved by interaction with the APC tumor suppressor. Here we show that binding of the armadillo repeats of APC to a 'core APC-binding' (CAB) motif within ASEF, or truncation of the SH3 domain of ASEF, relieves autoinhibition, allowing the specific activation of CDC42. Structural determination of autoinhibited ASEF reveals that the SH3 domain forms an extensive interface with the catalytic DH and PH domains to obstruct binding and activation of CDC42, and the CAB motif is positioned adjacent to the SH3 domain to facilitate activation by APC. In colorectal cancer cell lines, full-length, but not truncated, APC activates CDC42 in an ASEF-dependent manner to suppress anchorage-independent growth. We therefore propose a model in which ASEF acts as a tumor suppressor when activated by APC and inactivation of ASEF by mutation or APC truncation promotes tumorigenesis.
Release of autoinhibition of ASEF by APC leads to CDC42 activation and tumor suppression.,Mitin N, Betts L, Yohe ME, Der CJ, Sondek J, Rossman KL Nat Struct Mol Biol. 2007 Sep;14(9):814-23. Epub 2007 Aug 19. PMID:17704816[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kawasaki Y, Senda T, Ishidate T, Koyama R, Morishita T, Iwayama Y, Higuchi O, Akiyama T. Asef, a link between the tumor suppressor APC and G-protein signaling. Science. 2000 Aug 18;289(5482):1194-7. PMID:10947987
- ↑ Kawasaki Y, Sato R, Akiyama T. Mutated APC and Asef are involved in the migration of colorectal tumour cells. Nat Cell Biol. 2003 Mar;5(3):211-5. PMID:12598901 doi:10.1038/ncb937
- ↑ Hamann MJ, Lubking CM, Luchini DN, Billadeau DD. Asef2 functions as a Cdc42 exchange factor and is stimulated by the release of an autoinhibitory module from a concealed C-terminal activation element. Mol Cell Biol. 2007 Feb;27(4):1380-93. Epub 2006 Dec 4. PMID:17145773 doi:10.1128/MCB.01608-06
- ↑ Kawasaki Y, Sagara M, Shibata Y, Shirouzu M, Yokoyama S, Akiyama T. Identification and characterization of Asef2, a guanine-nucleotide exchange factor specific for Rac1 and Cdc42. Oncogene. 2007 Dec 6;26(55):7620-267. Epub 2007 Jun 18. PMID:17599059 doi:10.1038/sj.onc.1210574
- ↑ Kawasaki Y, Tsuji S, Muroya K, Furukawa S, Shibata Y, Okuno M, Ohwada S, Akiyama T. The adenomatous polyposis coli-associated exchange factors Asef and Asef2 are required for adenoma formation in Apc(Min/+)mice. EMBO Rep. 2009 Dec;10(12):1355-62. doi: 10.1038/embor.2009.233. Epub 2009 Nov 6. PMID:19893577 doi:10.1038/embor.2009.233
- ↑ Mitin N, Betts L, Yohe ME, Der CJ, Sondek J, Rossman KL. Release of autoinhibition of ASEF by APC leads to CDC42 activation and tumor suppression. Nat Struct Mol Biol. 2007 Sep;14(9):814-23. Epub 2007 Aug 19. PMID:17704816 doi:10.1038/nsmb1290
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