A RanGTP-independent mechanism allows ribosomal protein nuclear import for ribosome assembly.
Elife
; 3: e03473, 2014 Aug 21.
Article
en En
| MEDLINE
| ID: mdl-25144938
ABSTRACT
Within a single generation time a growing yeast cell imports â¼14 million ribosomal proteins (r-proteins) into the nucleus for ribosome production. After import, it is unclear how these intrinsically unstable and aggregation-prone proteins are targeted to the ribosome assembly site in the nucleolus. Here, we report the discovery of a conserved nuclear carrier Tsr2 that coordinates transfer of the r-protein eS26 to the earliest assembling pre-ribosome, the 90S. In vitro studies revealed that Tsr2 efficiently dissociates importineS26 complexes via an atypical RanGTP-independent mechanism that terminates the import process. Subsequently, Tsr2 binds the released eS26, shields it from proteolysis, and ensures its safe delivery to the 90S pre-ribosome. We anticipate similar carriers-termed here escortins-to securely connect the nuclear import machinery with pathways that deposit r-proteins onto developing pre-ribosomal particles.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Contexto en salud:
3_ND
Problema de salud:
3_neglected_diseases
/
3_zoonosis
Asunto principal:
Proteínas Ribosómicas
/
Ribosomas
/
Saccharomyces cerevisiae
/
Proteínas Portadoras
/
Núcleo Celular
Idioma:
En
Revista:
Elife
Año:
2014
Tipo del documento:
Article
País de afiliación:
Suiza