Required for the assembly of mature ribosomes and ribosome biogenesis. Together with EFL1, triggers the GTP-dependent release of EIF6 from 60S pre-ribosomes in the cytoplasm, thereby activating ribosomes for translation competence by allowing 80S ribosome assembly and facilitating EIF6 recycling to the nucleus, where it is required for 60S rRNA processing and nuclear export. Required for normal levels of protein synthesis. May play a role in cellular stress resistance. May play a role in cellular response to DNA damage. May play a role in cell proliferation. Associates with the 60S ribosomal subunit. Interacts with NPM1, RPA1 and PRKDC. May interact with NIP7 (PubMed:17643419). Found in a complex consisting of the 60S ribosomal subunit, SBDS and EFL1 (PubMed:26479198). Interacts with EFL1 (PubMed:25991726). Interacts with CLN3 (PubMed:20015955). Primarily detected in the cytoplasm, and at low levels in nucleus and nucleolus (PubMed:19602484 and PubMed:17475909). Detected in the nucleolus during G1 and G2 phase of the cell cycle, and diffusely distributed in the nucleus during S phase. Detected at the mitotic spindle. Colocalizes with the microtubule organizing center during interphase (PubMed:19759903). Widely expressed. The disease is caused by variants affecting the gene represented in this entry. Belongs to the SDO1/SBDS family. SBDS mutation db