Regulates transcription in association with TATA binding protein (TBP). Removes TBP from the TATA box via its C-terminal ATPase activity. Both transcription activation and repression require its ATPase activity (By similarity). Part of the NCT transcriptional regulatory complex that acts as a key regulator of ergosterol biosynthesis and the azole exporter cdr1B (PubMed:31969561). The NCT complex binds the promoters of genes linked to azole susceptibility, and especially represses the expression of cdr1B transporter (PubMed:31969561). Forms the NCT transcriptional regulatory complex with nctA and nctB. Belongs to the SNF2/RAD54 helicase family.