title: Reconstitution of two recombinant LSm protein complexes reveals aspects of their architecture, assembly, and function.
abstract: Sm and Sm-like (LSm) proteins form complexes engaging in various RNA-processing events. Composition and architecture of the complexes determine their intracellular distribution, RNA targets, and function. We have reconstituted the human LSm1-7 and LSm2-8 complexes from their constituent components in vitro. Based on the assembly pathway of the canonical Sm core domain, we used heterodimeric and heterotrimeric sub-complexes to assemble LSm1-7 and LSm2-8. Isolated sub-complexes form ring-like higher order structures. LSm1-7 is assembled and stable in the absence of RNA. LSm1-7 forms ring-like structures very similar to LSm2-8 at the EM level. Our in vitro reconstitution results illustrate likely features of the LSm complex assembly pathway. We prove the complexes to be functional both in an RNA bandshift and an in vivo cellular transport assay.
authors.affiliation: Paul Scherrer Institut, Biomolecular Research, CH5232 Villigen, Switzerland.
authors.forename: Bozidarka
authors.initials: B
authors.lastname: Zaric
authors.forename: Mohamed
authors.initials: M
authors.lastname: Chami
authors.forename: Hervé
authors.initials: H
authors.lastname: Rémigy
authors.forename: Andreas
authors.initials: A
authors.lastname: Engel
authors.forename: Kurt
authors.initials: K
authors.lastname: Ballmer-Hofer
authors.forename: Fritz K
authors.initials: FK
authors.lastname: Winkler
authors.forename: Christian
authors.initials: C
authors.lastname: Kambach
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism*; D002850:Chromatography, Gel; D003593:Cytoplasm / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008854:Microscopy, Electron; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D017411:Ribonucleoproteins, Small Nuclear