title: Proteins with two SUMO-like domains in chromatin-associated complexes: the RENi (Rad60-Esc2-NIP45) family.
abstract: BACKGROUND
  Post-translational modification by Small Ubiquitin-like Modifiers (SUMO) has been implicated in protein targeting, in the maintenance of genomic integrity and in transcriptional control. But the specific molecular effects of SUMO modification on many target proteins remain to be elucidated. Recent findings point at the importance of SUMO-mediated histone NAD-dependent deacetylase (HDAC) recruitment in transcriptional regulation.
  
  
  RESULTS
  We describe the RENi family of SUMO-like domain proteins (SDP) with the unique feature of typically containing two carboxy-terminal SUMO-like domains. Using sequence analytic evidence, we collect family members from animals, fungi and plants, most prominent being yeast Rad60, Esc2 and mouse NIP45 http://mendel.imp.univie.ac.at/SEQUENCES/reni/. Different proteins of the novel family are known to interact directly with histone NAD-dependent deacetylases (HDACs), structural maintenance of chromosomes (SMC) proteins, and transcription factors. In particular, the highly non-trivial designation of the first of the two successive SUMO-domains in non-plant RENi provides a rationale for previously published functionally impaired mutant variants.
  
  
  CONCLUSIONS
  Till now, SUMO-like proteins have been studied exclusively in the context of their covalent conjugation to target proteins. Here, we present the exciting possibility that SUMO domain proteins, similarly to ubiquitin modifiers, have also evolved in a second line - namely as multi-domain proteins that are non-covalently attached to their target proteins. We suggest that the SUMO stable fusion proteins of the RENi family, which we introduce in this work, might mimic SUMO and share its interaction motifs (in analogy to the way that ubiquitin-like domains mimic ubiquitin). This presumption is supported by parallels in the spectrum of modified or bound proteins e.g. transcription factors and chromatin-associated proteins and in the recruitment of HDAC-activity.
authors.affiliation: Gregor Mendel-Institut GMI, Austrian Academy of Sciences, Vienna Biocenter, A-1030 Vienna, Austria. maria.novatchkova@gmi.oeaw.ac.at
authors.forename: Maria
authors.initials: M
authors.lastname: Novatchkova
authors.forename: Andreas
authors.initials: A
authors.lastname: Bachmair
authors.forename: Birgit
authors.initials: B
authors.lastname: Eisenhaber
authors.forename: Frank
authors.initials: F
authors.lastname: Eisenhaber
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry; D019295:Computational Biology / Q000379:methods*; D003196:Computer Graphics; D005656:Fungal Proteins / Q000737:chemistry; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D005810:Multigene Family; D009687:Nuclear Proteins / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014157:Transcription Factors; D014158:Transcription, Genetic; D025801:Ubiquitin / Q000737:chemistry; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins
chemical_list: D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C102566:Nfatc2ip protein, mouse; D009687:Nuclear Proteins; D010940:Plant Proteins; D011506:Proteins; C455501:Rad60 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; D025801:Ubiquitin; D014452:Ubiquitins; D044763:Ubiquitin-Conjugating Enzymes; D006655:Histone Deacetylases