Cooperation of Multiple Chaperones Required for the Assembly of Mammalian 20S Proteasomes
| Autor: | Shigeo Murata, Toshihiko Kishimoto, Klavs B. Hendil, Shun-ichiro Iemura, Shin-ichiro Niwa, Masanori Kasahara, Hidemi Hayashi, Keiji Tanaka, Tohru Natsume, Yuko Hirano |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
chemistry.chemical_classification
Proteasome Endopeptidase Complex Gene knockdown biology Cell Biology Models Biological 20s proteasome Cell Line Cell biology Enzyme Proteasome chemistry Biochemistry Chaperone (protein) Proteasome assembly biology.protein Humans RNA Small Interfering Molecular Biology Gene Biogenesis Molecular Chaperones |
| Zdroj: | Molecular Cell. 24:977-984 |
| ISSN: | 1097-2765 |
| Popis: | The 20S proteasome is a catalytic core of the 26S proteasome, a central enzyme in the degradation of ubiquitin-conjugated proteins. It is composed of 14 distinct gene products that form four stacked rings of seven subunits each, alpha(1-7)beta(1-7)beta(1-7)alpha(1-7). It is reported that the biogenesis of mammalian 20S proteasomes is assisted by proteasome-specific chaperones, named PAC1, PAC2, and hUmp1, but the details are still unknown. Here, we report the identification of a chaperone, designated PAC3, as a component of alpha rings. Although it can intrinsically bind directly to both alpha and beta subunits, PAC3 dissociates before the formation of half-proteasomes, a process coupled with the recruitment of beta subunits and hUmp1. Knockdown of PAC3 impaired alpha ring formation. Further, PAC1/2/3 triple knockdown resulted in the accumulation of disorganized half-proteasomes that are incompetent for dimerization. Our results describe a cooperative system of multiple chaperones involved in the correct assembly of mammalian 20S proteasomes. |
| Databáze: | OpenAIRE |
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