Linked Life Data

21542805

Source:http://linkedlifedata.com/resource/pubmed/id/21542805

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2011-6-29
pubmed:abstractText
KLF5 (Krüppel-like factor 5) is a multifunctional transcription factor involved in cell proliferation, differentiation and carcinogenesis. In addition to frequent inactivation in different types of human cancers, including breast cancer, KLF5 has been identified as an essential co-factor for the TGF-? (transforming growth factor ?) tumour suppressor. In our previous study demonstrating a negative regulation of ER (oestrogen receptor ?) function by KLF5 in breast cancer cells [Guo, Dong, Zhao, Sun, Li and Dong (2010) Int. J. Cancer 126, 81-89], we noticed that oestrogen reduced the protein level of KLF5. In the present study, we have tested whether and how oestrogen/ER signalling regulates KLF5 protein. We found that oestrogen caused the degradation of KLF5 protein, and the degradation was sensitive to proteasome inhibitors, but not other inhibitors. The oestrogen-inducible E3 ligase EFP (oestrogen-responsive finger protein) was identified as a key player in oestrogen-mediated degradation of KLF5, as knockdown and overexpression of EFP increased and decreased KLF5 protein levels respectively, and the decrease continued even when protein synthesis was blocked. EFP-mediated degradation impaired the function of KLF5 in gene transcription. Although only unubiquitinated EFP interacted with KLF5, overexpression of EFP appeared to prevent the ubiquitination of KLF5, while resulting in heavy ubiquitination of the E3 itself. Furthermore, ubiquitination of EFP interrupted its interaction with KLF5. Although the mechanism for how EFP degrades KLF5 remains to be determined, the results of the present study suggest that oestrogen causes the degradation of KLF5 protein by inducing the expression of EFP in ER-positive breast cancer cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1470-8728
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
437
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
323-33
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Oestrogen causes degradation of KLF5 by inducing the E3 ubiquitin ligase EFP in ER-positive breast cancer cells.
pubmed:affiliation
Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, GA 30322, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural