InterPro domain: IPR045036

This entry includes senescence/dehydration-associated proteins from plants and Spartin from animals. This group of proteins share the C-terminal AAA ATPase domain [ 1 ].

Besides its C-terminal AAA ATPase domain, Spartin contains an N-terminal MIT (contained within microtubule-interacting and transport molecules) domain and a -P-P-x-Y- motif. Spastin monomers assemble into hexameric, ring-shaped ATPases that sever microtubules along their lengths [ 2 , 3 ]. In flies, Spartin has been shown to regulates both synaptic development and neuronal survival by controlling microtubule stability via the BMP-dFMRP-Futsch pathway [ 3 ]. In humans, Spartin (also known as SPG20) has been linked to Troyer syndrome, characterised by spastic dysarthria, cognitive impairment, short stature, and distal muscle wasting in addition to lower extremity spastic weakness [ 4 ]. SPG20 has been shown to be recruited to the midbody and participates in cytokinesis [ 5 ].

In plants, this group of proteins have been linked to senescence and dehydration [ 6 , 7 ]. Different from their animal homologues, they don't have the MIT domain. In Hemerocallis, petals have a genetically based program that leads to senescence and cell death approximately 24 hours after the, flower opens, and it is believed that senescence proteins produced around that time have a role in this program [ 8 ].

1. Structural basis of microtubule severing by the hereditary spastic paraplegia protein spastin. Nature 451, 363-7
2. The Drosophila homologue of the hereditary spastic paraplegia protein, spastin, severs and disassembles microtubules. Curr Biol 15, 650-5
3. Spartin regulates synaptic growth and neuronal survival by inhibiting BMP-mediated microtubule stabilization. Neuron 77, 680-95
4. SPG20 is mutated in Troyer syndrome, an hereditary spastic paraplegia. Nat Genet 31, 347-8
5. SPG20 protein spartin is recruited to midbodies by ESCRT-III protein Ist1 and participates in cytokinesis. Mol Biol Cell 21, 3293-303
6. Identification of senescence-associated genes from daylily petals. Plant Mol. Biol. 40, 237-48
7. Cloning of cDNAs for genes that are early-responsive to dehydration stress (ERDs) in Arabidopsis thaliana L.: identification of three ERDs as HSP cognate genes. Plant Mol Biol 25, 791-8