title: Linking axonal degeneration to microtubule remodeling by Spastin-mediated microtubule severing.
abstract: Mutations in the AAA adenosine triphosphatase (ATPase) Spastin (SPG4) cause an autosomal dominant form of hereditary spastic paraplegia, which is a retrograde axonopathy primarily characterized pathologically by the degeneration of long spinal neurons in the corticospinal tracts and the dorsal columns. Using recombinant Spastin, we find that six mutant forms of Spastin, including three disease-associated forms, are severely impaired in ATPase activity. In contrast to a mutation designed to prevent adenosine triphosphate (ATP) binding, an ATP hydrolysis-deficient Spastin mutant predicted to remain kinetically trapped on target proteins decorates microtubules in transfected cells. Analysis of disease-associated missense mutations shows that some more closely resemble the canonical hydrolysis mutant, whereas others resemble the ATP-binding mutant. Using real-time imaging, we show that Spastin severs microtubules when added to permeabilized, cytosol-depleted cells stably expressing GFP-tubulin. Using purified components, we also show that Spastin interacts directly with microtubules and is sufficient for severing. These studies suggest that defects in microtubule severing are a cause of axonal degeneration in human disease.
authors.affiliation: Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
authors.forename: Katia J
authors.initials: KJ
authors.lastname: Evans
authors.forename: Edgar R
authors.initials: ER
authors.lastname: Gomes
authors.forename: Steven M
authors.initials: SM
authors.lastname: Reisenweber
authors.forename: Gregg G
authors.initials: GG
authors.lastname: Gundersen
authors.forename: Brett P
authors.initials: BP
authors.lastname: Lauring
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001369:Axons / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008870:Microtubules / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D041681:NIH 3T3 Cells; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D015419:Spastic Paraplegia, Hereditary / Q000235:genetics / Q000378:metabolism*; D000074181:Spastin; D014404:Tubulin / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D014404:Tubulin; D000251:Adenosine Triphosphatases; D000074181:Spastin; C400283:SPAST protein, human; C498515:Spast protein, mouse
references.citation: J Med Genet. 2003 Feb;40(2):81-6
references.pmid: 12566514
references.citation: Science. 1999 Oct 22;286(5440):782-5
references.pmid: 10531065
references.citation: Nat Genet. 2003 Apr;33(4):455-6
references.pmid: 12627231
references.citation: Genomics. 2003 Apr;81(4):437-41
references.pmid: 12676568
references.citation: Nat Genet. 1999 Nov;23(3):296-303
references.pmid: 10610178
references.citation: Hum Mol Genet. 2000 Mar 1;9(4):637-44
references.pmid: 10699187
references.citation: FEBS Lett. 2000 Mar 17;470(1):93-5
references.pmid: 10722852
references.citation: J Med Genet. 2000 Oct;37(10):759-65
references.pmid: 11015453
references.citation: J Cell Sci. 2000 Nov;113 ( Pt 22):3907-19
references.pmid: 11058078
references.citation: J Cell Sci. 2001 May;114(Pt 9):1601-2
references.pmid: 11309190
references.citation: Genes Cells. 2001 Jul;6(7):575-97
references.pmid: 11473577
references.citation: Annu Rev Neurosci. 2001;24:1121-59
references.pmid: 11520930
references.citation: Nature. 2001 Dec 6;414(6864):652-6
references.pmid: 11740563
references.citation: Hum Mol Genet. 2002 Jan 15;11(2):153-63
references.pmid: 11809724
references.citation: Mol Cell. 2002 Apr;9(4):751-60
references.pmid: 11983167
references.citation: Ann Neurol. 2002 Jun;51(6):669-72
references.pmid: 12112070
references.citation: Hum Mol Genet. 2003 Jan 1;12(1):71-8
references.pmid: 12490534
references.citation: J Cell Biol. 2003 Jul 7;162(1):71-84
references.pmid: 12847084
references.citation: J Neurobiol. 2003 Dec;57(3):291-302
references.pmid: 14608664
references.citation: J Neuropathol Exp Neurol. 2003 Nov;62(11):1166-77
references.pmid: 14656074
references.citation: Mol Biol Cell. 2004 Feb;15(2):637-48
references.pmid: 14617820
references.citation: J Struct Biol. 2004 Apr-May;146(1-2):2-10
references.pmid: 15037233
references.citation: J Struct Biol. 2004 Apr-May;146(1-2):106-12
references.pmid: 15095758
references.citation: J Neurosci. 2004 Jun 23;24(25):5778-88
references.pmid: 15215300
references.citation: Mol Biol Cell. 2004 Jul;15(7):3123-31
references.pmid: 15121885
references.citation: Curr Biol. 2004 Jul 13;14(13):1135-47
references.pmid: 15242610
references.citation: Cell. 1984 Oct;38(3):779-89
references.pmid: 6386177
references.citation: Cell. 1993 Nov 5;75(3):419-29
references.pmid: 8221885
references.citation: J Cell Sci. 1994 Jun;107 ( Pt 6):1593-607
references.pmid: 7962200
references.citation: EMBO J. 1997 Apr 15;16(8):1820-31
references.pmid: 9155008
references.citation: J Biol Chem. 1998 Apr 3;273(14):8439-46
references.pmid: 9525956
references.citation: Cell. 1998 Apr 17;93(2):277-87
references.pmid: 9568719
references.citation: EMBO J. 1998 Jun 1;17(11):2982-93
references.pmid: 9606181
references.citation: J Biol Chem. 1998 Jun 19;273(25):15546-52
references.pmid: 9624144
references.citation: Mol Biol Cell. 1998 Jul;9(7):1847-61
references.pmid: 9658175
references.citation: FEBS Lett. 1998 Sep 18;435(2-3):211-4
references.pmid: 9762911
references.citation: J Cell Biol. 1999 Apr 19;145(2):305-15
references.pmid: 10209026
references.citation: PLoS Biol. 2004 Dec;2(12):e429
references.pmid: 15562320
references.citation: Hum Mol Genet. 2005 Jan 1;14(1):19-38
references.pmid: 15537668
references.citation: Biochemistry. 2003 Mar 11;42(9):2595-606
references.pmid: 12614154