Part of the SNAPc complex required for the transcription of both RNA polymerase II and III small-nuclear RNA genes. Binds to the proximal sequence element (PSE), a non-TATA-box basal promoter element common to these 2 types of genes. Recruits TBP and BRF2 to the U6 snRNA TATA box. This is the function of Ensembl gene identifier ENSG00000174446 (SNAPC5, small nuclear RNA activating complex polypeptide 5).