CRISPR screens reveal ZBTB17/MIZ1 as a peroxisome regulator

Peroxisomes are integral metabolic organelles involved in both catabolic and anabolic processes in humans, with defects often linked to diseases. The functions of peroxisomes are regulated at transcriptional, translational, and post-translational levels. In this study, we employed the CRISPR/Cas9-based genetic screening of a ubiquitin ligase library to identify regulators of human peroxisomes. We discovered that ZBTB17 (also referred as MIZ1) plays a role in regulating the import of proteins into peroxisomes. Independent of its ubiquitin ligase activity, ZBTB17/MIZ1 operates as a transcription factor to directly modulate the expression of key importer PEX13, thereby influencing the localization of peroxisomal enzymes. Furthermore, metabolomic profiling reveals that the knockdown of ZBTB17 or PEX13 results in similar metabolic alterations, characterized by downregulated purine synthesis, suggesting that ZBTB17s role in metabolic regulation likely operates through peroxisomes. Collectively, we identify ZBTB17 as a key regulator of peroxisomal protein import, thereby affecting peroxisomal function and nucleotide metabolism. Our findings provide insights into the multifaceted regulation of peroxisomes in complex human cells and shed light on the molecular mechanisms underlying ZBTB17s role as a transcriptional regulator.