smn1 Antibody

The SMN complex catalyzes the assembly of small nuclear ribonucleoproteins (snRNPs), the building blocks of the spliceosome, and thereby plays an important role in the splicing of cellular pre-mRNAs. Most spliceosomal snRNPs contain a common set of Sm proteins smb1, smd1, smd2, smd3, sme1, smf1 and smg1 that assemble in a heptameric protein ring on the Sm site of the small nuclear RNA to form the core snRNP (Sm core). In the cytosol, the Sm proteins smd1, smd2, sme1, smf1 and smg1 (5Sm) are trapped in an inactive 6S pICln-Sm complex by the chaperone saf5 that controls the assembly of the core snRNP. To assemble core snRNPs, the SMN complex accepts the trapped 5Sm proteins from saf5 forming an intermediate. Binding of snRNA inside 5Sm triggers eviction of the SMN complex, thereby allowing binding of smd3 and smb1 to complete assembly of the core snRNP. Within the SMN complex, smn1 acts as a structural backbone and together with yip11/gem2 it gathers the Sm complex subunits.