Synchronizing Nuclear Import of Ribosomal Proteins with Ribosome Assembly.

The article discusses synchronization of the nuclear import of ribosomal proteins with ribosome assembly. The authors note that the synthesis of ribosomal proteins occurs in the cytoplasm prior to nuclear import and assembly with ribosomal RNA (rRNA), but little is known about the coordination of nucleocytoplasmic transport with ribosome assembly. Topics include the authors' identification of a transport adaptor, called symportin 1 (Syo1), that facilitates synchronized co-import of the two 5S-rRNA binding proteins Rpl5 and Rpl11, how Syo1 binds Rpl5-Rplll and recruits the import receptor Kap104, and how symportin-mediated co-import of RplS-Rplll could ensure the coordinated and stoichiometric incorporation of these proteins into pre-60S ribosomes.