The Ras signaling inhibitor LOX-PP interacts with Hsp70 and c-Raf to reduce Erk activation and transformed phenotype of breast cancer cells.
Mol Cell Biol
; 31(13): 2683-95, 2011 Jul.
Article
de En
| MEDLINE
| ID: mdl-21536655
The lysyl oxidase gene (LOX) inhibits Ras signaling in transformed fibroblasts and breast cancer cells. Its activity was mapped to the 162-amino-acid propeptide domain (LOX-PP) of the lysyl oxidase precursor protein. LOX-PP inhibits Erk signaling, motility, and tumor formation in a breast cancer xenograft model; however, its mechanism of action is largely unknown. Here, a copurification-mass spectrometry approach was taken using ectopically expressed LOX-PP in HEK293T cells and the heat shock/chaperone protein Hsp70 identified. Hsp70 interaction with LOX-PP was confirmed using coimmunoprecipitation of intracellularly and bacterially expressed and endogenous proteins. The interaction was mapped to the Hsp70 peptide-binding domain and to LOX-PP amino acids 26 to 100. LOX-PP association reduced Hsp70 chaperone activities of protein refolding and survival after heat shock. LOX-PP interacted with the Hsp70 chaperoned protein c-Raf. With the use of ectopic expression of LOX-PP wild-type and deletion proteins, small interfering RNA (siRNA) knockdown, and Lox(-/-) mouse embryo fibroblasts, LOX-PP interaction with c-Raf was shown to decrease downstream activation of MEK and NF-κB, migration, and anchorage-independent growth and reduce its mitochondrial localization. Thus, the interaction of LOX-PP with Hsp70 and c-Raf inhibits a critical intermediate in Ras-induced MEK signaling and plays an important role in the function of this tumor suppressor.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Tumeurs du sein
/
Protéines G ras
/
Protéines du choc thermique HSP70
/
Lysyloxidase
Type d'étude:
Prognostic_studies
Limites:
Animals
/
Female
/
Humans
Langue:
En
Journal:
Mol Cell Biol
Année:
2011
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique
Pays de publication:
États-Unis d'Amérique