spastin: ATP-dependent microtubule severing protein. Microtubule severing may promote reorganization of cellular microtubule arrays and the release of microtubules from the centrosome following nucleation. Required for membrane traffic from the endoplasmic reticulum (ER) to the Golgi and for completion of the abscission stage of cytokinesis. May also play a role in axon growth and the formation of axonal branches. Defects in SPAST are the cause of spastic paraplegia autosomal dominant type 4 (SPG4). Spastic paraplegia is a neurodegenerative disorder characterized by a slow, gradual, progressive weakness and spasticity of the lower limbs. Rate of progression and the severity of symptoms are quite variable. Initial symptoms may include difficulty with balance, weakness and stiffness in the legs, muscle spasms, and dragging the toes when walking. In some forms of the disorder, bladder symptoms (such as incontinence) may appear, or the weakness and stiffness may spread to other parts of the body. SPG4 is the most common form of autosomal dominant spastic paraplegias. Belongs to the AAA ATPase family. Spastin subfamily. 4 isoforms of the human protein are produced by alternative promoter.
Protein type: EC 3.6.4.3; Cytoskeletal; Membrane protein, integral
Cellular Component: centrosome; cytoplasm; cytoplasmic vesicle; endoplasmic reticulum; endosome; integral to membrane; membrane; microtubule; microtubule cytoskeleton; midbody; nuclear membrane; nucleus; perinuclear region of cytoplasm; spindle
Molecular Function: alpha-tubulin binding; ATP binding; beta-tubulin binding; microtubule binding; microtubule-severing ATPase activity
Biological Process: anterograde axon cargo transport; axon transport of mitochondrion; axonogenesis; cytokinesis after mitosis; cytokinetic process; cytoplasmic microtubule organization and biogenesis; ER to Golgi vesicle-mediated transport; exit from mitosis; microtubule bundle formation; microtubule severing; mitotic spindle disassembly; nuclear envelope reassembly; positive regulation of cytokinesis; positive regulation of microtubule depolymerization; protein homooligomerization
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