Ribosome stalk assembly requires the dual-specificity phosphatase Yvh1 for the exchange of Mrt4 with P0.
The ribosome stalk is essential for recruitment of translation factors. In yeast, P0 and Rpl12 correspond to bacterial L10 and L11 and form the stalk base of mature ribosomes, whereas Mrt4 is a nuclear paralogue of P0. In this study, we show that the dual-specificity phosphatase Yvh1 is required for the release of Mrt4 from the pre-60S subunits. Deletion of YVH1 leads to the persistence of Mrt4 on pre-60S subunits in the cytoplasm. A mutation in Mrt4 at the protein-RNA interface bypasses the requirement for Yvh1. Pre-60S subunits associated with Yvh1 contain Rpl12 but lack both Mrt4 and P0. These results suggest a linear series of events in which Yvh1 binds to the pre-60S subunit to displace Mrt4. Subsequently, P0 loads onto the subunit to assemble the mature stalk, and Yvh1 is released. The initial assembly of the ribosome with Mrt4 may provide functional compartmentalization of ribosome assembly in addition to the spatial separation afforded by the nuclear envelope.
Department of Chemistry and Biochemistry, Section of Molecular Genetics and Microbiology, The Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
Kai-Yin
KY
Lo
Zhihua
Z
Li
Feng
F
Wang
Edward M
EM
Marcotte
Arlen W
AW
Johnson
D001665:Binding Sites; D054637:Dual-Specificity Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D006367:HeLa Cells; D006801:Humans; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D034622:RNA Interference; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054683:Ribosome Subunits, Large, Eukaryotic / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
C121972:MRT4 protein, S cerevisiae; C056002:RPP0 protein, S cerevisiae; D012269:Ribosomal Proteins; C525863:Rpl12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C489855:dual specificity phosphatase 12; D054637:Dual-Specificity Phosphatases; C121559:YVH1 protein, S cerevisiae