Survival of motor neuron

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Survival motor neuron protein
Protein SMN1 PDB 1g5v.png
Tudor domain from human SMN. PDB 1g5v[1]
Symbol SMN
Pfam PF06003
Pfam clan CL0049
InterPro IPR010304
SCOP 1mhn

Survival of motor neuron or survival motor neuron (SMN) is a protein that in humans is encoded by the SMN1 and SMN2 genes.

SMN is found in the cytoplasm of all animal cells and also in the nuclear gems. It functions in transcriptional regulation, telomerase regeneration and cellular trafficking.[2] SMN deficiency, primarily due to mutations in SMN1, results in widespread splicing defects, especially in spinal motor neurons, and is one cause of spinal muscular atrophy. Research also showed a possible role of SMN in neuronal migration and/or differentiation.[3]

Evolutionary conservation[edit]

SMN is evolutionarily conserved including the Fungi kingdom, though only fungal organisms with a great number of introns have the Smn gene (or the splicing factor spf30 paralogue). Surprisingly, these are filamentous fungus which have mycelia, so suggesting analogy to the neuronal axons.[4]

SMN complex[edit]

SMN complex refers to the entire multi-protein complex involved in the assembly of snRNPs, the essential components of spliceosomal machinery.[5] The complex, apart from the "proper" survival of motor neuron protein, includes at least six other proteins (gem-associated proteins 2–7) [5]

See also[edit]


  1. ^ Selenko P, Sprangers R, Stier G, Bühler D, Fischer U, Sattler M (January 2001). "SMN tudor domain structure and its interaction with the Sm proteins". Nature Structural Biology. 8 (1): 27–31. PMID 11135666. doi:10.1038/83014. 
  2. ^ Singh NN, Shishimorova M, Cao LC, Gangwani L, Singh RN (2009). "A short antisense oligonucleotide masking a unique intronic motif prevents skipping of a critical exon in spinal muscular atrophy". RNA Biology. 6 (3): 341–50. PMC 2734876Freely accessible. PMID 19430205. doi:10.4161/rna.6.3.8723. 
  3. ^ Giavazzi A, Setola V, Simonati A, Battaglia G (March 2006). "Neuronal-specific roles of the survival motor neuron protein: evidence from survival motor neuron expression patterns in the developing human central nervous system". Journal of Neuropathology and Experimental Neurology. 65 (3): 267–77. PMID 16651888. doi:10.1097/01.jnen.0000205144.54457.a3. 
  4. ^ Mier P, Pérez-Pulido AJ (January 2012). "Fungal Smn and Spf30 homologues are mainly present in filamentous fungi and genomes with many introns: implications for spinal muscular atrophy". Gene. 491 (2): 135–41. PMID 22020225. doi:10.1016/j.gene.2011.10.006. 
  5. ^ a b Gubitz AK, Feng W, Dreyfuss G (May 2004). "The SMN complex". Experimental Cell Research. 296 (1): 51–6. PMID 15120993. doi:10.1016/j.yexcr.2004.03.022. 

External links[edit]