Survival motor neuron protein - Q16637 (SMN_HUMAN)


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The SMN complex plays a catalyst role in the assembly of small nuclear ribonucleoproteins (snRNPs), the building blocks of the spliceosome. 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. 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. Dissociation by the SMN complex of CLNS1A from the trapped Sm proteins and their transfer to an SMN-Sm complex triggers the assembly of core snRNPs and their transport to the nucleus. 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). UniProt
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Subunit Structure
Homodimer (PubMed:14715275). Part of the core SMN complex that contains SMN1, GEMIN2/SIP1, DDX20/GEMIN3, GEMIN4, GEMIN5, GEMIN6, GEMIN7, GEMIN8 and STRAP/UNRIP (PubMed:9323129). 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 (PubMed:12065586, PubMed:18984161). Component of an import snRNP complex composed of KPNB1, RNUT1, SMN1 and ZNF259 (PubMed:12095920). Interacts with DDX20, FBL, NOLA1, RNUT1, SYNCRIP and with several spliceosomal snRNP core Sm proteins, including SNRPB, SNRPD1, SNRPD2, SNRPD3, SNRPE and ILF3 (PubMed:11574476, PubMed:12095920). Interacts with OSTF1, LSM10, LSM11 and RPP20/POP7 (PubMed:11551898, PubMed:12975319, PubMed:16087681, PubMed:14715275). Interacts (via C-terminal region) with ZPR1 (via C-terminal region) (PubMed:11283611). Interacts (via Tudor domain) with COIL (PubMed:11641277). Interacts with SETX; recruits SETX to POLR2A (PubMed:21700224, PubMed:26700805). Interacts with POLR2A (via the C-terminal domain (CTD)) (PubMed:26700805). Interacts with PRMT5 (PubMed:26700805). Interacts with XRN2 (PubMed:26700805). Interacts (via C-terminus) with FMR1 (via C-terminus); the interaction is direct and occurs in a RNA-independent manner (PubMed:18093976). Interacts (via Tudor domain) with SF3B2 ('Arg-508'-methylated form) (PubMed:25737013). Interacts with WRAP53/TCAB1 (PubMed:21072240). Interacts (via Tudor domain) with ELAVL4 in an RNA-independent manner; the interaction is required for localization of ELAVL4 to RNA granules (PubMed:21088113, PubMed:21389246, PubMed:29061699). UniProt
The Tudor domain mediates association with dimethylarginines, which are common in snRNP proteins. UniProt
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