PT  - JOURNAL ARTICLE
AU  - van den Heuvel, Jasmin
AU  - Ashiono, Caroline
AU  - Gillet, Ludovic
AU  - Dörner, Kerstin
AU  - Wyler, Emanuel
AU  - Zemp, Ivo
AU  - Kutay, Ulrike
TI  - Processing of the Ribosomal Ubiquitin-Like Fusion Protein FUBI-eS30/FAU is Required for 40S Maturation and Depends on USP36
AID  - 10.1101/2021.05.21.445149
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.05.21.445149
4099  - http://biorxiv.org/content/early/2021/05/22/2021.05.21.445149.short
4100  - http://biorxiv.org/content/early/2021/05/22/2021.05.21.445149.full
AB  - In humans and other holozoan organisms, the ribosomal protein eS30 is synthesized as a fusion protein with the ubiquitin-like protein FUBI. However, FUBI is not part of the mature 40S ribosomal subunit and cleaved off by an as-of-yet unidentified protease. How FUBI-eS30 processing is coordinated with 40S subunit maturation is unknown. To study the mechanism and importance of FUBI-eS30 processing, we expressed non-cleavable mutants in human cells, which affected late steps of cytoplasmic 40S maturation, including the maturation of 18S rRNA and recycling of late-acting ribosome biogenesis factors. Differential affinity purification of wild-type and non-cleavable FUBI-eS30 mutants identified the deubiquitinase USP36 as a candidate FUBI-eS30 processing enzyme. Depletion of USP36 by RNAi or CRISPRi indeed impaired FUBI-eS30 processing and moreover, purified USP36 cut FUBI-eS30 in vitro. Together, these data demonstrate the functional importance of FUBI-eS30 cleavage and identify USP36 as a novel protease involved in this process.Competing Interest StatementThe authors have declared no competing interest.