title: The SMN Tudor SIM-like domain is key to SmD1 and coilin interactions and to Cajal body biogenesis.
abstract: Cajal bodies (CBs) are nuclear organelles involved in the maturation of spliceosomal small nuclear ribonucleoproteins (snRNPs). They concentrate coilin, snRNPs and the survival motor neuron protein (SMN). Dysfunction of CB assembly occurs in spinal muscular atrophy (SMA). Here, we demonstrate that SMN is a SUMO1 target that has a small ubiquitin-related modifier (SUMO)-interacting motif (SIM)-like motif in the Tudor domain. The expression of SIM-like mutant constructs abolishes the interaction of SMN with the spliceosomal SmD1 (also known as SNRPD1), severely decreases SMN-coilin interaction and prevents CB assembly. Accordingly, the SMN SIM-like-mediated interactions are important for CB biogenesis and their dysfunction can be involved in SMA pathophysiology.
authors.affiliation: Department of Anatomy and Cell Biology, University of Cantabria-IFIMAV, Santander E-39008, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Tapia
authors.forename: Vanesa
authors.initials: V
authors.lastname: Lafarga
authors.forename: Rocio
authors.initials: R
authors.lastname: Bengoechea
authors.forename: Ana
authors.initials: A
authors.lastname: Palanca
authors.forename: Miguel
authors.initials: M
authors.lastname: Lafarga
authors.forename: María T
authors.initials: MT
authors.lastname: Berciano
mesh_terms: D000595:Amino Acid Sequence; D020541:Coiled Bodies / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D061986:MCF-7 Cells; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D021381:Protein Transport; D025842:SUMO-1 Protein / Q000378:metabolism; D017381:Spliceosomes / Q000378:metabolism; D058207:Sumoylation; D055533:Survival of Motor Neuron 1 Protein / Q000378:metabolism*; D055517:snRNP Core Proteins / Q000378:metabolism*
chemical_list: D009687:Nuclear Proteins; C526409:SNRPD1 protein, human; D025842:SUMO-1 Protein; C495501:SUMO1 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055517:snRNP Core Proteins; C068921:p80-coilin
keywords: Cajal body; SIM; SMN; SUMO1; Sm complex