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:20887893, PubMed:17505538). 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). Interacts with TFIIIB subunits BRF1 and BRF2 (PubMed:17505538, PubMed:18377933). Interacts with Pol III subunit POLR3F. Interacts with TFIIIC subunit GTF3C1 (PubMed:18377933). Phosphorylated at Ser-60, Ser-68 and Ser-75; the major sites of phosphorylation. Nuclear accumulation correlates with a concomitant dephosphorylation. Phosphorylation may attenuate its RNA polymerase III-repressive function. Sumoylated with SUMO1 and SUMO2, mainly on Lys-35. Desumoylated by SENP1. SUMOylation promotes the ability of MAF1 to repress transcription and suppress colony formation. Belongs to the MAF1 family.