Component of a multiprotein complex required for the assembly of the RNA endonuclease module of the integrator complex (PubMed:39032489). Associates with INTS9 and INTS11 in the cytoplasm, stabilizing the INTS9-INTS11 heterodimer and blocking the active site of INTS11 (PubMed:39032489). BRAT1 then joins the complex and plugs the active site of INTS11, leading to WDR73 release and nuclear import of INTS9 and INTS11 (PubMed:39032489). . This is the function of Ensembl gene identifier ENSG00000177082 (WDR73, WD repeat domain 73).