Document Detail


Cell cycle regulation of the human Six1 homeoprotein is mediated by APC(Cdh1).
MedLine Citation:
PMID:  17130831     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The Six1 homeoprotein is an important mediator of normal development, where it is critical for the proliferation of precursor cell populations that ultimately constitute the muscle, kidney and inner ear, among other organs. Interestingly, its overexpression has been observed in numerous cancers, where it contributes to the proliferative and metastatic ability of the cancer cells. Here we show that Six1 not only regulates the cell cycle, but is itself regulated throughout the cell cycle via ubiquitin-mediated proteolysis. The protein is present from the G(1)/S boundary until mitosis, when it is degraded via the anaphase-promoting complex (APC) with its activating subunit Cdh1. However, unlike most identified APC(Cdh1) targets, Six1 does not contain functional destruction or KEN box motifs that are necessary for its degradation. Instead, the Six1 protein contains multiple, as yet undefined, sequences within its N- and C-termini responsible for its degradation, including an N-terminal region that binds to Cdh1. Cell cycle regulation of Six1 occurs both transcriptionally and post-translationally via phosphorylation; therefore, this study demonstrates a third and novel mechanism of cell cycle-specific regulation of Six1, underscoring the importance of confining its activity to a defined cell cycle window from the G(1)/S boundary to early mitosis.
Authors:
K L Christensen; J D G Brennan; C S Aldridge; H L Ford
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2006-11-20
Journal Detail:
Title:  Oncogene     Volume:  26     ISSN:  0950-9232     ISO Abbreviation:  Oncogene     Publication Date:  2007 May 
Date Detail:
Created Date:  2007-05-17     Completed Date:  2007-06-18     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  8711562     Medline TA:  Oncogene     Country:  England    
Other Details:
Languages:  eng     Pagination:  3406-14     Citation Subset:  IM    
Affiliation:
Program in Molecular Biology, University of Colorado at Denver and Health Sciences Center, Fitzsimons Campus, Aurora, CO, USA.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Motifs
Amino Acid Sequence
Cadherins / genetics,  metabolism*
Cell Cycle*
Cell Line, Tumor
Cell Nucleus / metabolism
Homeodomain Proteins / chemistry,  genetics,  metabolism*
Humans
Proteasome Endopeptidase Complex / metabolism
Protein Binding
Ubiquitin / metabolism
Grant Support
ID/Acronym/Agency:
R01 CA095277/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/CDH1 protein, human; 0/Cadherins; 0/Homeodomain Proteins; 0/SIX1 protein, human; 0/Ubiquitin; EC 3.4.25.1/Proteasome Endopeptidase Complex

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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