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 (By similarity). Most spliceosomal snRNPs contain a common set of Sm proteins SNRPB, SNRPD1, SNRPD2, SNRPD3, SNRPE, SNRPF and SNRPG that assemble in a heptameric protein ring on the Sm site of the small nuclear RNA to form the core snRNP (Sm core) (By similarity). In the cytosol, the Sm proteins SNRPD1, SNRPD2, SNRPE, SNRPF and SNRPG (5Sm) are trapped in an inactive 6S pICln-Sm complex by the chaperone CLNS1A that controls the assembly of the core snRNP (By similarity). To assemble core snRNPs, the SMN complex accepts the trapped 5Sm proteins from CLNS1A (By similarity). Binding of snRNA inside 5Sm ultimately triggers eviction of the SMN complex, thereby allowing binding of SNRPD3 and SNRPB to complete assembly of the core snRNP (By similarity). Within the SMN complex, GEMIN2 constrains the conformation of 5Sm, thereby promoting 5Sm binding to snRNA containing the snRNP code (a nonameric Sm site and a 3'-adjacent stem-loop), thus preventing progression of assembly until a cognate substrate is bound (By similarity). Monomer (By similarity). Part of the core SMN complex that contains SMN1, GEMIN2/SIP1, DDX20/GEMIN3, GEMIN4, GEMIN5, GEMIN6, GEMIN7, GEMIN8 and STRAP/UNRIP. Part of the SMN-Sm complex that contains SMN1, GEMIN2/SIP1, DDX20/GEMIN3, GEMIN4, GEMIN5, GEMIN6, GEMIN7, GEMIN8, STRAP/UNRIP and the Sm proteins SNRPB, SNRPD1, SNRPD2, SNRPD3, SNRPE, SNRPF and SNRPG (By similarity). Interacts with GEMIN5; the interaction is direct (By similarity). Interacts (via C-terminus) with SMN1; the interaction is direct (By similarity). Interacts with GEMIN5; the interaction is direct (By similarity). Interacts with SNRPD1; the interaction is direct (By similarity). Interacts with SNRPD2; the interaction is direct (By similarity). Interacts (via N-terminus) with SNRPF; the interaction is direct (By similarity). Interacts (via N-terminus) with SNRPE; the interaction is direct (By similarity). Interacts (via N-terminus) with SNRPG; the interaction is direct (By similarity). Localized in subnuclear structures next to coiled bodies, called gems, which are highly enriched in spliceosomal snRNPs. Also found in the cytoplasm (By similarity). Belongs to the gemin-2 family.