title: Synchronizing nuclear import of ribosomal proteins with ribosome assembly.
abstract: Ribosomal proteins are synthesized in the cytoplasm, before nuclear import and assembly with ribosomal RNA (rRNA). Little is known about coordination of nucleocytoplasmic transport with ribosome assembly. Here, we identify a transport adaptor, symportin 1 (Syo1), that facilitates synchronized coimport of the two 5S-rRNA binding proteins Rpl5 and Rpl11. In vitro studies revealed that Syo1 concomitantly binds Rpl5-Rpl11 and furthermore recruits the import receptor Kap104. The Syo1-Rpl5-Rpl11 import complex is released from Kap104 by RanGTP and can be directly transferred onto the 5S rRNA. Syo1 can shuttle back to the cytoplasm by interaction with phenylalanine-glycine nucleoporins. X-ray crystallography uncovered how the α-solenoid symportin accommodates the Rpl5 amino terminus, normally bound to 5S rRNA, in an extended groove. Symportin-mediated coimport of Rpl5-Rpl11 could ensure coordinated and stoichiometric incorporation of these proteins into pre-60S ribosomes.
authors.affiliation: Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg D-69120, Germany. dieter.kressler@unifr.ch
authors.forename: Dieter
authors.initials: D
authors.lastname: Kressler
authors.forename: Gert
authors.initials: G
authors.lastname: Bange
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Goran
authors.initials: G
authors.lastname: Stjepanovic
authors.forename: Bettina
authors.initials: B
authors.lastname: Bradatsch
authors.forename: Dagmar
authors.initials: D
authors.lastname: Pratte
authors.forename: Stefan
authors.initials: S
authors.lastname: Amlacher
authors.forename: Daniela
authors.initials: D
authors.lastname: Strauß
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yoneda
authors.forename: Jun
authors.initials: J
authors.lastname: Katahira
authors.forename: Irmgard
authors.initials: I
authors.lastname: Sinning
authors.forename: Ed
authors.initials: E
authors.lastname: Hurt
mesh_terms: D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D002597:Chaetomium / Q000378:metabolism; D018360:Crystallography, X-Ray; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D012331:RNA, Fungal / Q000378:metabolism; D012341:RNA, Ribosomal, 5S / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D028961:beta Karyopherins / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; C101820:KAP104 protein, S cerevisiae; D012331:RNA, Fungal; D012341:RNA, Ribosomal, 5S; D016601:RNA-Binding Proteins; C489268:RPL5 protein, S cerevisiae; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; D028961:beta Karyopherins; C027937:ribosomal protein L16