Clastosome: A Subtype of Nuclear Body Enriched in 19S and 20S Proteasomes, Ubiquitin, and Protein Substrates of Proteasome
AUTOR(ES)
Lafarga, Miguel
FONTE
The American Society for Cell Biology
RESUMO
Nuclear bodies represent a heterogeneous class of nuclear structures. Herein, we describe that a subset of nuclear bodies is highly enriched in components of the ubiquitin–proteasome pathway of proteolysis. We coined the term clastosome (from the Greek klastos, broken and soma, body) to refer to this type of nuclear body. Clastosomes contain a high concentration of 1) ubiquitin conjugates, 2) the proteolytically active 20S core and the 19S regulatory complexes of the 26S proteasome, and 3) protein substrates of the proteasome. Although detected in a variety of cell types, clastosomes are scarce under normal conditions; however, they become more abundant when proteasomal activity is stimulated. In contrast, clastosomes disappear when cells are treated with proteasome inhibitors. Protein substrates of the proteasome that are found concentrated in clastosomes include the short-lived transcription factors c-Fos and c-Jun, adenovirus E1A proteins, and the PML protein. We propose that clastosomes are sites where proteolysis of a variety of protein substrates is taking place.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=117941Documentos Relacionados
- Crystallization and preliminary X-ray analysis of the Thermoplasma acidophilum 20S proteasome in complex with protein substrates
- Identification and characterization of a mammalian protein interacting with 20S proteasome precursors
- The 20S Proteasome of Streptomyces coelicolor
- Subunit arrangement in the human 20S proteasome
- Subunit Topology of Two 20S Proteasomes from Haloferax volcanii