Identification of new interacting partners of the shuttling protein ubinuclein (Ubn-1).
Exp Cell Res
; 318(5): 509-20, 2012 Mar 10.
Article
em En
| MEDLINE
| ID: mdl-22245583
ABSTRACT
We have previously characterized ubinuclein (Ubn-1) as a NACos (Nuclear and Adherent junction Complex components) protein which interacts with viral or cellular transcription factors and the tight junction (TJ) protein ZO-1. The purpose of the present study was to get more insights on the binding partners of Ubn-1, notably those present in the epithelial junctions. Using an in vivo assay of fluorescent protein-complementation assay (PCA), we demonstrated that the N-terminal domains of the Ubn-1 and ZO-1 proteins triggered a functional interaction inside the cell. Indeed, expression of both complementary fragments of venus fused to the N-terminal parts of Ubn-1 and ZO-1 was able to reconstitute a fluorescent venus protein. Furthermore, nuclear expression of the chimeric Ubn-1 triggered nuclear localization of the chimeric ZO-1. We could localize this interaction to the PDZ2 domain of ZO-1 using an in vitro pull-down assay. More precisely, a 184-amino acid region (from amino acids 39 to 223) at the N-terminal region of Ubn-1 was responsible for the interaction with the PDZ2 domain of ZO-1. Co-imunoprecipitation and confocal microscopy experiments also revealed the tight junction protein cingulin as a new interacting partner of Ubn-1. A proteomic approach based on mass spectrometry analysis (MS) was then undertaken to identify further binding partners of GST-Ubn-1 fusion protein in different subcellular fractions of human epithelial HT29 cells. LYRIC (Lysine-rich CEACAM1-associated protein) and RACK-1 (receptor for activated C-kinase) proteins were validated as bona fide interacting partners of Ubn-1. Altogether, these results suggest that Ubn-1 is a scaffold protein influencing protein subcellular localization and is involved in several processes such as cell-cell contact signalling or modulation of gene activity.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fosfoproteínas
/
Fatores de Transcrição
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Proteínas Nucleares
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Proteínas de Membrana
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Proteínas dos Microfilamentos
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Exp Cell Res
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
França