Part of the small subunit (SSU) processome, first precursor of the small eukaryotic ribosomal subunit. During the assembly of the SSU processome in the nucleolus, many ribosome biogenesis factors, an RNA chaperone and ribosomal proteins associate with the nascent pre- rRNA and work in concert to generate RNA folding, modifications, rearrangements and cleavage as well as targeted degradation of pre- ribosomal RNA by the RNA exosome. Acts as a chaperone that specifically mediates the integration of RPS19 in state post-A1 (PubMed:34516797). Direct regulator of SIRT1. Enhances SIRT1-mediated deacetylation of p53/TP53, thereby participating in inhibition of p53/TP53-mediated transcriptional activity (PubMed:17964266). . This is the function of RPS19BP1 (ribosomal protein S19 binding protein 1, Ensembl gene identifier ENSG00000187051).