Association of the mammalian proto‐oncoprotein Int‐6 with the three protein complexes eIF3, COP9 signalosome and 26S proteasome

FEBS Letters

Réty, Stéphane¹  Jalinot, Pierre¹  Bochard, Valérie¹  Hoareau Alves, Karine¹ 

[1] Laboratoire de Biologie Moléculaire et Cellulaire, UMR5665–Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, 46, Allée d'Italie, 69364 Lyon Cedex 07, France

关键词: Int-6;    COP9 signalosome;    26S Proteasome;    eIF3;    Two-hybrid;    eIF;    eukaryotic translation initiation factor;    CSN;    COP9 (constitutive photomorphogenesis 9) signalosome;    MMTV;    mouse mammary tumor virus;    PCI;    proteasome–COP9 signalosome–initiation factor 3;    MPN;    Mpr1–Pad1–N-terminal domain;    SCF;    Skip–Cullin–F box;    SDS–PAGE;    sodium dodecyl sulfate–polyacrylamide gel electrophoresis;   

DOI  :  10.1016/S0014-5793(02)03147-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The mammalian Int-6 protein has been characterized as a subunit of the eIF3 translation initiation factor and also as a transforming protein when its C-terminal part is deleted. It includes a protein domain, which also exists in various subunits of eIF3, of the 26S proteasome and of the COP9 signalosome (CSN). By performing a two-hybrid screen with Int-6 as bait, we have isolated subunits belonging to all three complexes, namely eIF3-p110, Rpt4, CSN3 and CSN6. The results of transient expression experiments in COS7 cells confirmed the interaction of Int-6 with Rpt4, CSN3 and CSN6, but also showed that Int-6 is able to bind another subunit of the CSN: CSN7a. Immunoprecipitation experiments performed with the endogenous proteins showed that Int-6 binds the entire CSN, but in low amount, and also that Int-6 is associated with the 26S proteasome. Taken together these results show that the Int-6 protein can bind the three complexes with various efficiencies, possibly exerting a regulatory activity in both protein translation and degradation.

【 授权许可】

Unknown