The function of TAF1C (TATA-box binding protein associated factor, RNA polymerase I subunit C, ENSG00000103168) is as follows. Component of the transcription factor SL1/TIF-IB complex, which is involved in the assembly of the PIC (pre-initiation complex) during RNA polymerase I-dependent transcription. The rate of PIC formation probably is primarily dependent on the rate of association of SL1/TIF-IB with the rDNA promoter. SL1/TIF-IB is involved in stabilization of nucleolar transcription factor 1/UBTF on rDNA. Formation of SL1/TIF-IB excludes the association of TBP with TFIID subunits. Recruits RNA polymerase I to the rRNA gene promoter via interaction with RRN3. {ECO:0000269|PubMed:11250903, ECO:0000269|PubMed:11283244, ECO:0000269|PubMed:15970593}.