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 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). In the cytosol, the Sm proteins SNRPD1, SNRPD2, SNRPE, SNRPF and SNRPG are trapped in an inactive 6S pICln-Sm complex by the chaperone CLNS1A that controls the assembly of the core snRNP. To assemble core snRNPs, the SMN complex accepts the trapped 5Sm proteins from CLNS1A forming an intermediate. 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. Within the SMN complex, SMN1 acts as a structural backbone and together with GEMIN2 it gathers the Sm complex subunits. Ensures the correct splicing of U12 intron-containing genes that may be important for normal motor and proprioceptive neurons development. Also required for resolving RNA-DNA hybrids created by RNA polymerase II, that form R-loop in transcription terminal regions, an important step in proper transcription termination. May also play a role in the metabolism of small nucleolar ribonucleoprotein (snoRNPs). Homooligomer; may form higher order homooligomers in the dimer to octamer range. 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. Component of an import snRNP complex composed of KPNB1, RNUT1, SMN1 and ZNF259. Interacts with DDX20, FBL, NOLA1, RNUT1, SYNCRIP and with several spliceosomal snRNP core Sm proteins, including SNRPB, SNRPD1, SNRPD2, SNRPD3, SNRPE and ILF3. Interacts with GEMIN2; the interaction is direct. Interacts with GEMIN3; the interaction is direct. Interacts with GEMIN8; the interaction is direct. Interacts with SNRPB; the interaction is direct. Interacts (via Tudor domain) with SNRPD1 (via C-terminus); the interaction is direct. Interacts with SNRPD2; the interaction is direct. Interacts (via Tudor domain) with SNRPD3 (via C-terminus); the interaction is direct. Interacts with SNRPE; the interaction is direct. Interacts with OSTF1, LSM10, LSM11 and RPP20/POP7. Interacts (via C-terminal region) with ZPR1 (via C-terminal region). Interacts (via Tudor domain) with COIL. Interacts with SETX; recruits SETX to POLR2A. Interacts with POLR2A (via the C-terminal domain (CTD)). Interacts with PRMT5. Interacts with XRN2. Interacts (via C-terminus) with FMR1 (via C-terminus); the interaction is direct and occurs in a RNA-independent manner. Interacts (via Tudor domain) with SF3B2 ('Arg-508'-methylated form). Interacts with WRAP53/TCAB1. Interacts (via Tudor domain) with ELAVL4 in an RNA-independent manner; the interaction is required for localization of ELAVL4 to RNA granules. Interacts with FRG1. Colocalizes with actin and at the Z-line of skeletal muscle (By similarity). Under stress conditions colocalizes with RPP20/POP7 in punctuated cytoplasmic granules. Colocalized and redistributed with ZPR1 from the cytoplasm to nuclear gems (Gemini of coiled bodies) and Cajal bodies. Colocalizes with FMR1 in cytoplasmic granules in the soma and neurite cell processes (By similarity). The Tudor domain mediates association with dimethylarginines, which are common in snRNP proteins. Belongs to the SMN family.