title: Sem1: a versatile "molecular glue"?
abstract: The evolutionary conserved protein Sem1/Dss1 is a bona fide subunit of the regulatory particle (RP) of the proteasome and in mammalian cells stabilizes the tumor suppressor protein BRCA2. A recent study from our laboratory has revealed an unexpected non- proteasomal role of Sem1 in mRNA export. We found that Sem1, independent of the RP, is a functional component of the nuclear pore associated TREX-2 complex that is directly involved in the dynamic relocalization of a subset of DNA loci to the nuclear periphery. Like other components of TREX-2, Sem1 is required for proper nuclear export of mRNAs, transcription elongation and preventing transcription-associated genomic instability. Strikingly, Sem1 associates with a third multi-subunit protein complex namely the COP9 signalosome, which is involved in de-neddylation. We propose that Sem1 is a versatile protein that regulates the functional integrity of multiple protein complexes involved in diverse biological pathways.
authors.affiliation: Institute of Biochemistry (IBC), ETH Zürich, Zürich, Switzerland.
authors.forename: Marius Boulos
authors.initials: MB
authors.lastname: Faza
authors.forename: Stefan
authors.initials: S
authors.lastname: Kemmler
authors.forename: Vikram Govind
authors.initials: VG
authors.lastname: Panse
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D000818:Animals; D005090:Exodeoxyribonucleases / Q000378:metabolism; D042822:Genomic Instability; D006899:Mixed Function Oxygenases / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D055550:Protein Stability; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: C117424:SEM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D006899:Mixed Function Oxygenases; D000123:Acetyltransferases; C120564:Sac3 protein kinase; D017346:Protein Serine-Threonine Kinases; D005090:Exodeoxyribonucleases; D046988:Proteasome Endopeptidase Complex