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N-terminal Gemin2-binding domain of the Survival Motor Neuron family The survival motor neuron (SMN) protein family includes metazoan SMN and fungal SMN-like protein 1 (SMN1). SMN forms the oligomeric core of a multiprotein complex, called the SMN complex, that functions in the assembly and biogenesis of small nuclear ribonucleoproteins (snRNPs), the building blocks of the spliceosome. It is expressed in all tissues of metazoan organisms, but is particularly expressed at high levels in motor neurons. Schizosaccharomyces pombe SMN1 is essential for viability and has been shown to interact with human SMN and Sm proteins. Loss of function mutations in the SMN gene of humans cause spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. While most eukaryotes have a single copy of the SMN gene, humans have two; the telomeric SMN1 gene is deleted or mutated in SMA patients, whereas the centromeric SMN2 gene is unaffected and can be present in multiple copies. SMN has three highly conserved domains: a short N-terminal region that is responsible for binding with high affinity to Gemin2; a central Tudor domain that recognizes symmetric dimethylarginine (sDMA) modifications in arginine/glycine rich regions of a number of proteins involved in RNA processing, including the Sm proteins; and a C-terminal domain called the YG-box that is primarily responsible for oligomerization. This model represents the N-terminal Gemin2-binding domain of SMN family proteins. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",