InterPro domain: IPR033867

Mrt4 is a ribosomal stalk protein P0 (or Rpp0) paralogue involved in ribosome biogenesis and mRNA turnover [ 1 , 2 ]. P0 is cytoplasmic and is present in cytoplasmic pre-60S particles and mature 60S subunits. Mrt4, however, is nuclear and has been identified in pre-60S ribosome complexes but not in mature 60S subunits, suggesting that it binds ribosomes at an early stage of assembly in the nucleolus and during assembly it is exchanged for P0. The dual-specificity phosphatase Yvh1 is required for Mrt4 displacement from the pre-60S subunit [ 3 ]. P0 is required for the release of Mrt4 and exchanges with this factor at the cytoplasm [ 4 ].

1. Composition and functional characterization of yeast 66S ribosome assembly intermediates. Mol. Cell 8, 505-15
2. Temperature-sensitive mutations in the Saccharomyces cerevisiae MRT4, GRC5, SLA2 and THS1 genes result in defects in mRNA turnover. Genetics 153, 35-47
3. Ribosome stalk assembly requires the dual-specificity phosphatase Yvh1 for the exchange of Mrt4 with P0. J. Cell Biol. 186, 849-62
4. Role and dynamics of the ribosomal protein P0 and its related trans-acting factor Mrt4 during ribosome assembly in Saccharomyces cerevisiae. Nucleic Acids Res. 37, 7519-32