MAF1
Description
The MAF1 (MAF1 homolog, negative regulator of RNA polymerase III) is a protein-coding gene located on chromosome 8.
MAF1 is a human protein encoded by the MAF1 gene. It is homologous to the yeast protein Maf1, which is highly conserved in eukaryotic cells. MAF1 acts as a negative effector of RNA polymerase III (Pol III) transcription, responding to cellular environmental changes and repressing Pol III activity. Biochemical studies have identified the initiation factor TFIIIB as a target for MAF1-mediated repression.
MAF1 plays a key role in regulating RNA polymerase III transcription, ensuring a balance between the production of essential small RNAs like tRNAs and 5S rRNA and cell growth. It achieves this by responding to changes in cellular conditions, particularly nutrient availability and stress. When nutrients are plentiful, MAF1 is hyperphosphorylated, allowing RNA polymerase III to actively transcribe. Under stress, MAF1 is dephosphorylated, leading to its nuclear localization and suppression of RNA polymerase III transcription. Additionally, MAF1 may regulate RNA polymerase I and II activity through its influence on the expression of the transcription initiation factor TBP. MAF1 interacts with several key components of the transcription machinery, including TFIIIB subunits BRF1 and BRF2, the Pol III subunit POLR3F, and TFIIIC subunit GTF3C1.
