spastin ATP-dependent microtubule severing protein that specifically recognizes and cuts microtubules that are polyglutamylated. Preferentially recognizes and acts on microtubules decorated with short polyglutamate tails: severing activity increases as the number of glutamates per tubulin rises from one to eight, but decreases beyond this glutamylation threshold. Severing activity is not dependent on tubulin acetylation or detyrosination. Microtubule severing promotes reorganization of cellular microtubule arrays and the release of microtubules from the centrosome following nucleation. It is critical for the biogenesis and maintenance of complex microtubule arrays in axons, spindles and cilia. SPAST is involved in abscission step of cytokinesis and nuclear envelope reassembly during anaphase in cooperation with the ESCRT-III complex. Recruited at the midbody, probably by IST1, and participates in membrane fission during abscission together with the ESCRT-III complex. Recruited to the nuclear membrane by IST1 and mediates microtubule severing, promoting nuclear envelope sealing and mitotic spindle disassembly during late anaphase. Required for membrane traffic from the endoplasmic reticulum (ER) to the Golgi and endosome recycling. Recruited by IST1 to endosomes and regulates early endosomal tubulation and recycling by mediating microtubule severing. Probably plays a role in axon growth and the formation of axonal branches. Isoform 1: Involved in lipid metabolism by regulating the size and distribution of lipid droplets. Belongs to the AAA ATPase family. Spastin subfamily. Expressed in brain, heart, kidney, liver, lung, pancreas, placenta and skeletal muscle. The short isoforms may predominate in brain and spinal cord. 4 human isoforms generated by alternative promoter usage, alternative splicing or alternative initiation have been reported. Note: This description may include information from UniProtKB.
Protein type: Cytoskeletal; EC 3.6.4.3; Membrane protein, integral
Chromosomal Location of Human Ortholog: 2p22.3
Cellular Component:  axon cytoplasm; centrosome; cytoplasm; cytoplasmic vesicle; cytosol; endoplasmic reticulum membrane; integral component of membrane; lipid droplet; microtubule; midbody; nuclear membrane; nucleoplasm; nucleus; perinuclear region of cytoplasm; spindle
Molecular Function:  alpha-tubulin binding; ATP binding; beta-tubulin binding; isomerase activity; microtubule binding; microtubule-severing ATPase activity; protein binding; protein-containing complex binding
Biological Process:  anterograde axonal transport; axonal transport of mitochondrion; axonogenesis; cytokinetic process; cytoskeleton-dependent cytokinesis; ER to Golgi vesicle-mediated transport; exit from mitosis; membrane fission; metabolic process; microtubule bundle formation; microtubule severing; mitotic cytokinesis; mitotic spindle disassembly; nuclear envelope reassembly; positive regulation of cytokinesis; positive regulation of microtubule depolymerization; protein hexamerization; protein homooligomerization
Disease: Spastic Paraplegia 4, Autosomal Dominant
Reference #:  Q9UBP0 (UniProtKB)
Alt. Names/Synonyms: ADPSP; FSP2; KIAA1083; SPAST; spastic paraplegia 4 (autosomal dominant; Spastic paraplegia 4 protein; Spastin; spastin); SPG4
Gene Symbols: SPAST
Molecular weight: 67,197 Da
Basal Isoelectric point: 9.67  Predict pI for various phosphorylation states
Select Structure to View Below

spastin

Protein Structure Not Found.


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