GEMIN5

This gene encodes a WD repeat protein that is a component of the survival of motor neurons (SMN) complex. The SMN complex plays a critical role in mRNA splicing through the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs), and may also mediate the assembly and transport of other classes of ribonucleoproteins. The encoded protein is the snRNA-binding component of the SMN complex. Dysregulation of this gene may play a role in alternative mRNA splicing and tumor cell motility. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene.

Full Name

gem nuclear organelle associated protein 5

Function

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 (PubMed:16857593, PubMed:18984161, PubMed:20513430).

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 (PubMed:18984161).

To assemble core snRNPs, the SMN complex accepts the trapped 5Sm proteins from CLNS1A forming an intermediate (PubMed:18984161).

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, GEMIN5 recognizes and delivers the small nuclear RNAs (snRNAs) to the SMN complex (PubMed:11714716, PubMed:16857593, PubMed:19377484, PubMed:19750007, PubMed:20513430, PubMed:27834343, PubMed:27881600, PubMed:27881601, PubMed:16314521).

Binds to the 7-methylguanosine cap of RNA molecules (PubMed:19750007, PubMed:27834343, PubMed:27881600, PubMed:27881601, Ref. 27).

Binds to the 3'-UTR of SMN1 mRNA and regulates its translation; does not affect mRNA stability (PubMed:25911097).

May play a role in the regulation of protein synthesis via its interaction with ribosomes (PubMed:27507887).

Biological Process

mRNA splicing, via spliceosome Source: UniProtKB
Protein-containing complex assembly Source: UniProtKB
Regulation of translation Source: UniProtKB
Spliceosomal snRNP assembly Source: UniProtKB
Translation Source: UniProtKB-KW

Cellular Location

Cytoplasm; Nucleoplasm; Gem. Found both in the nucleoplasm and in nuclear bodies called gems (Gemini of Cajal bodies) that are often in proximity to Cajal (coiled) bodies. Also found in the cytoplasm.