Plays a role in the repression of RNA polymerase III-mediated transcription in response to changing nutritional, environmental and cellular stress conditions to balance the production of highly abundant tRNAs, 5S rRNA, and other small non-coding RNAs with cell growth and maintenance (PubMed:18377933, PubMed:20233713, PubMed:20516213, PubMed:20543138). Also plays a key role in cell fate determination by promoting mesorderm induction and adipocyte differentiation (By similarity). Mechanistically, associates with the RNA polymerase III clamp and thereby impairs its recruitment to the complex made of the promoter DNA, TBP and the initiation factor TFIIIB (PubMed:17505538, PubMed:20887893). When nutrients are available and mTOR kinase is active, MAF1 is hyperphosphorylated and RNA polymerase III is engaged in transcription. Stress-induced MAF1 dephosphorylation results in nuclear localization, increased targeting of gene-bound RNA polymerase III and a decrease in the transcriptional readout (PubMed:26941251). Additionally, may also regulate RNA polymerase I and RNA polymerase II- dependent transcription through its ability to regulate expression of the central initiation factor TBP (PubMed:17499043). {ECO:0000250|UniProtKB:Q9D0U6, ECO:0000269|PubMed:17499043, ECO:0000269|PubMed:17505538, ECO:0000269|PubMed:18377933, ECO:0000269|PubMed:20233713, ECO:0000269|PubMed:20516213, ECO:0000269|PubMed:20543138, ECO:0000269|PubMed:20887893, ECO:0000269|PubMed:26941251}. This is the function of ENSG00000179632 (MAF1, MAF1 negative regulator of RNA polymerase III).