The SMN complex catalyzes the assembly of small nuclearribonucleoproteins (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 proteinsSNRPB, SNRPD1, SNRPD2, SNRPD3, SNRPE, SNRPF and SNRPG that assemble ina heptameric protein ring on the Sm site of the small nuclear RNA toform the core snRNP (Sm core). In the cytosol, the Sm proteins SNRPD1, SNRPD2, SNRPE, SNRPF and SNRPG are trapped in an inactive 6S pICln-Smcomplex by the chaperone CLNS1A that controls the assembly of the coresnRNP. To assemble core snRNPs, the SMN complex accepts the trapped 5Smproteins from CLNS1A forming an intermediate. Binding of snRNA inside5Sm triggers eviction of the SMN complex, thereby allowing binding ofSNRPD3 and SNRPB to complete assembly of the core snRNP. STRAP plays arole in the cellular distribution of the SMN complex. Negativelyregulates TGF-beta signaling but positively regulates the PDPK1 kinaseactivity by enhancing its autophosphorylation and by significantlyreducing the association of PDPK1 with 14-3-3 protein. [1-2]

MAMRQTPLTCSGHTRPVVDLAFSGITPYGYFLISACKDGKPMLRQGDTGDWIGTFLGHKGAVWGATLNKDATKAATAAADFTAKVWDAVSGDELMTLAHKHIVKTVDFTQDSNYLLTGGQDKLLRIYDLNKPEAEPKEISGHTSGIKKALWCSEDKQILSADDKTVRLWDHATMTEVKSLNFNMSVSSMEYIPEGEILVITYGRSIAFHSAVSLDPIKSFEAPATINSASLHPEKEFLVAGGEDFKLYKYDYNSGEELESYKGHFGPIHCVRFSPDGELYASGSEDGTLRLWQTVVGKTYGLWKCVLPEEDSGELAKPKIGFPETTEEELEEIASENSDCIFPSAPDVKA