The C-terminal α-helix of SPAS-1, a Caenorhabditis elegans spastin homologue, is crucial for microtubule severing

Caenorhabditis elegans Models of Hereditary Spastic Paraplegia

“…This indicates that the MIT domain is not necessary for the microtubule cutting function, but the MTBD domain is required for this interaction. This function was apparently lost when SPAS-1 1-432 and SPAS-1 1-435 were expressed in the heterologous cells, indicating that the microtubule-severing activity was absent in these two truncated forms of SPAS-1 (Onitake et al, 2012). Expression of SPAS-1 WT and SPAS 1-447 in HEK293 cells resulted in the disappearance of the microtubule network, indicating that the microtubule-severing function of SPAS-1 was intact (Figure 74.1).…”

“…Two transcripts are present: one with a full-length protein consisting of 454 amino acids and another lacking exon 4. This α-helix structure is highly conserved within the AAA family of proteins, especially within the meiotic AAA subfamily (Onitake et al, 2012). The MIT domain is not very homologous with its human homolog, but the MTBD and AAA domains are highly conserved (Matsushita-Ishiodori et al, 2007).…”