title: The SUMO system controls nucleolar partitioning of a novel mammalian ribosome biogenesis complex.
abstract: Ribosome biogenesis is a tightly controlled pathway that requires an intricate spatial and temporal interplay of protein networks. Most structural rRNA components are generated in the nucleolus and assembled into pre-ribosomal particles, which are transferred for further maturation to the nucleoplasm and cytoplasm. In metazoa, few regulatory components for these processes have been characterized. Previous work revealed a critical role for the SUMO-specific protease SENP3 in the nucleolar steps of ribosome biogenesis. We biochemically purified a SENP3-associated complex comprising PELP1, TEX10 and WDR18, and demonstrate that this complex is involved in maturation and nucleolar release of the large ribosomal subunit. We identified PELP1 and the PELP1-associated factor LAS1L as SENP3-sensitive targets of SUMO, and provide evidence that balanced SUMO conjugation/deconjugation determines the nucleolar partitioning of this complex. This defines the PELP1-TEX10-WDR18 complex as a regulator of ribosome biogenesis and suggests that its SUMO-controlled distribution coordinates the rate of ribosome formation. These findings contribute to the basic understanding of mammalian ribosome biogenesis and shed new light on the role of SUMO in this process.
authors.affiliation: Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Finkbeiner
authors.forename: Markus
authors.initials: M
authors.lastname: Haindl
authors.forename: Stefan
authors.initials: S
authors.lastname: Muller
mesh_terms: D002460:Cell Line; D056970:Co-Repressor Proteins; D003546:Cysteine Endopeptidases / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D021381:Protein Transport; D012270:Ribosomes / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism; D058207:Sumoylation; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors
chemical_list: D056970:Co-Repressor Proteins; C552426:Las1L protein, human; D009687:Nuclear Proteins; C438485:PELP1 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; C558247:TEX10 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; C558249:WDR18 protein, human; D003546:Cysteine Endopeptidases; C499718:SENP3 protein, human