Ribosome-binding protein 1, RRBP1, maintains peroxisomal biogenesis

Peroxisomes are single membrane-bound organelles essential for human health, yet the mechanism of peroxisomal biogenesis remains poorly described. Here using a systematic double screening approach, we identified ribosome-binding protein 1, RRBP1, as a novel peroxisomal biogenesis factor in human cells. We showed that the number of peroxisomes and the levels of peroxisomal proteins are reduced by RRBP1 KO in HEK293T cells. In addition, the processing of peroxisomal matrix proteins, such as ACOX1 and thiolase was affected in RRBP1 KO HEK293T cells. Using electron microscopy, we showed that RRBP1, an ER membrane protein, is involved in the maintaining of the long-distance contact sites between ER and peroxisomal membranes, suggesting that the role of RRBP1 in peroxisomal biogenesis is mediated through inter-organellar contact sites. Altogether our results showed that RRBP1 promotes peroxisomal biogenesis in human cells highlighting the power of systematic approaches in discovering novel factors of organellar biogenesis.