General activator of RNA polymerase III transcription. Factor exclusively required for RNA polymerase III transcription of genes with promoter elements upstream of the initiation sites (PubMed:11040218, PubMed:11121026, PubMed:11564744, PubMed:26638071). Contributes to the regulation of gene expression; functions as activator in the absence of oxidative stress (PubMed:26638071). Down-regulates expression of target genes in response to oxidative stress (PubMed:26638071). Overexpression protects cells against apoptosis in response to oxidative stress (PubMed:26638071). Component of TFIIIB complexes. The TFIIIB complex has two activities, alpha and beta. The TFIIIB-alpha activity complex is composed of TBP, BDP1, and a complex containing both BRF2 and at least four stably associated proteins; this complex inhibits the transcription by pol III via its phosphorylation by CK2; YY1 facilitates the TFIIIB-alpha complex formation. Interacts with TBP; this interaction promotes recruitment of BRF2 to TATA box-containing promoters (PubMed:26638071). Interacts with TBP and the BURE sequence (GC-rich sequence downstream from the TATA box) to form a strong ternary complex which is joined by BDP1; this ternary complex stimulates pol III transcription. Forms a trimeric complex composed of TBP, BRF2 and mini-SNAPc complex (SNAP43, SNAP50, and the N-terminal third of SNAP190) on the promoter. Assembly of the TBP-BRF2 complex is stimulated by SNAP190. Interacts with MAF1 and SNAPC4. Down-regulated by epigallocatechin gallate (EGCG) treatment. In response to oxidative stress, Cys-361 is reversibly oxidized to cysteine sulfenic acid. Oxidation of Cys-361 impairs formation of a ternary complex with TBP and DNA and down-regulates expression of target genes in response to oxidative stress. Belongs to the TFIIB family.