title: Tau mutants bind tubulin heterodimers with enhanced affinity.
abstract: Tau is a microtubule binding protein that forms pathological aggregates in the brain in Alzheimer's disease and other tauopathies. Disease etiology is thought to arise from loss of native interactions between tau and microtubules, as well as from gain of toxicity tied to tau aggregation, although neither mechanism is well understood. Here we investigate the link between function and disease using disease-associated and disease-motivated mutants of tau. We find that mutations to highly conserved proline residues in repeats 2 and 3 of the microtubule binding domain have differential effects on tau binding to tubulin and the capacity of tau to enhance tubulin polymerization. Notably, mutations to these residues result in an increased affinity for tubulin dimers while having a negligible effect on binding to stabilized microtubules. We measure conformational changes in tau on binding to tubulin that provide a structural framework for the observed altered affinity and function. Additionally, we find that these mutations do not necessarily enhance aggregation, which could have important implications for tau therapeutic strategies that focus solely on searching for tau aggregation inhibitors. We propose a model that describes tau binding to tubulin dimers and a mechanism by which disease-relevant alterations to tau impact its function. Together, these results draw attention to the interaction between tau and free tubulin as playing an important role in mechanisms of tau pathology.
authors.affiliation: Departments of Molecular Biophysics and Biochemistry, Chemistry, and Physics, Yale University, New Haven, CT 06511.
authors.forename: Shana
authors.initials: S
authors.lastname: Elbaum-Garfinkle
authors.forename: Garrett
authors.initials: G
authors.lastname: Cobb
authors.forename: Jocelyn T
authors.initials: JT
authors.lastname: Compton
authors.forename: Xiao-Han
authors.initials: XH
authors.lastname: Li
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Rhoades
mesh_terms: D031541:Fluorescence Resonance Energy Transfer; D007700:Kinetics; D008958:Models, Molecular; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D058105:Polymerization; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D020449:Repetitive Sequences, Amino Acid; D014404:Tubulin / Q000737:chemistry* / Q000378:metabolism*; D016875:tau Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D050505:Mutant Proteins; D014404:Tubulin; D016875:tau Proteins
keywords: intrinsically disordered proteins; microtubule-associated protein; single molecule FRET
references.citation: J Biol Chem. 2008 Dec 26;283(52):36406-15
references.pmid: 18940799
references.citation: Proc Natl Acad Sci U S A. 2000 May 9;97(10):5129-34
references.pmid: 10805776
references.citation: Neuron. 1989 Jun;2(6):1615-24
references.pmid: 2516729
references.citation: J Cell Biol. 1985 Nov;101(5 Pt 1):1799-807
references.pmid: 2997236
references.citation: Biochemistry. 2009 Oct 27;48(42):10047-55
references.pmid: 19769346
references.citation: J Cell Biol. 1998 Nov 2;143(3):777-94
references.pmid: 9813097
references.citation: J Alzheimers Dis. 2012;31(4):741-9
references.pmid: 22699846
references.citation: J Biol Chem. 2006 Apr 28;281(17):11856-63
references.pmid: 16495230
references.citation: Biochemistry. 2009 Mar 24;48(11):2304-6
references.pmid: 19220042
references.citation: J Cell Biol. 1995 Dec;131(5):1327-40
references.pmid: 8522593
references.citation: FEBS Lett. 1999 Mar 26;447(2-3):195-9
references.pmid: 10214944
references.citation: Brain Pathol. 2007 Jan;17(1):91-103
references.pmid: 17493043
references.citation: Mol Biol Cell. 1992 Oct;3(10):1141-54
references.pmid: 1421571
references.citation: EMBO J. 2003 Jan 2;22(1):70-7
references.pmid: 12505985
references.citation: Nat Rev Drug Discov. 2009 Oct;8(10):783-93
references.pmid: 19794442
references.citation: J Mol Biol. 2006 Sep 15;362(2):312-26
references.pmid: 16908029
references.citation: Eur J Biochem. 1985 Dec 16;153(3):595-600
references.pmid: 3935441
references.citation: J Cell Biol. 2002 Jun 24;157(7):1187-96
references.pmid: 12082079
references.citation: Ann Neurol. 1999 Nov;46(5):708-15
references.pmid: 10553987
references.citation: Biochemistry. 2000 Sep 26;39(38):11714-21
references.pmid: 10995239
references.citation: Annu Rev Neurosci. 2001;24:1121-59
references.pmid: 11520930
references.citation: FEBS Lett. 1992 Jul 28;307(2):199-205
references.pmid: 1644173
references.citation: Biochemistry. 2004 Aug 17;43(32):10520-31
references.pmid: 15301550
references.citation: J Am Chem Soc. 2012 Oct 10;134(40):16607-13
references.pmid: 22998648
references.citation: Neurology. 2001 Jun;56(11 Suppl 4):S21-5
references.pmid: 11402146
references.citation: Cold Spring Harb Perspect Med. 2012 Jul;2(7):a006247
references.pmid: 22762014
references.citation: Biochemistry. 2000 May 23;39(20):6136-44
references.pmid: 10821687
references.citation: Nat Rev Neurosci. 2007 Sep;8(9):663-72
references.pmid: 17684513
references.citation: Ann N Y Acad Sci. 1986;466:257-68
references.pmid: 2873777
references.citation: Cell. 1978 Aug;14(4):795-804
references.pmid: 688394
references.citation: Proc Natl Acad Sci U S A. 2004 Apr 27;101(17):6746-51
references.pmid: 15096589
references.citation: J Mol Biol. 1977 Oct 25;116(2):227-47
references.pmid: 146092
references.citation: J Biol Chem. 2005 Jul 1;280(26):24978-86
references.pmid: 15855160
references.citation: J Cell Biol. 1994 Mar;124(5):769-82
references.pmid: 8120098
references.citation: Mol Biol Cell. 2004 Jun;15(6):2720-8
references.pmid: 15020716
references.citation: Biochemistry. 1998 Dec 22;37(51):17692-703
references.pmid: 9922135
references.citation: Biochemistry. 1994 Aug 16;33(32):9511-22
references.pmid: 8068626
references.citation: J Cell Biol. 1991 Nov;115(3):717-30
references.pmid: 1918161
references.citation: Neuron. 2011 May 12;70(3):410-26
references.pmid: 21555069
references.citation: J Biol Chem. 2000 Dec 8;275(49):38182-9
references.pmid: 10984497
references.citation: Brain Res Brain Res Rev. 2000 Aug;33(1):95-130
references.pmid: 10967355
references.citation: Nature. 1992 Dec 17;360(6405):674-7
references.pmid: 1465130
references.citation: Science. 1998 Dec 4;282(5395):1914-7
references.pmid: 9836646
references.citation: Mol Biol Cell. 2001 Jan;12(1):171-84
references.pmid: 11160831
references.citation: Biochimie. 2012 Mar;94(3):916-9
references.pmid: 21958522
references.citation: Protein Sci. 2013 Aug;22(8):1037-48
references.pmid: 23740819
references.citation: Mol Biol Cell. 1997 Feb;8(2):353-65
references.pmid: 9190213
references.citation: J Cell Sci. 2004 Dec 1;117(Pt 25):6129-41
references.pmid: 15564376
references.citation: J Biol Chem. 2000 Sep 29;275(39):30335-43
references.pmid: 10869348
references.citation: Nature. 1998 Jun 18;393(6686):702-5
references.pmid: 9641683
references.citation: EMBO J. 2008 Jan 23;27(2):336-49
references.pmid: 18216876
references.citation: Ann Med. 1989;21(2):127-32
references.pmid: 2504257
references.citation: Neuromolecular Med. 2002;2(2):151-65
references.pmid: 12428809
references.citation: FEBS Lett. 1998 Oct 23;437(3):207-10
references.pmid: 9824291
references.citation: Mol Biol Cell. 1995 Dec;6(12):1887-902
references.pmid: 8590813
references.citation: J Biol Chem. 2011 Jan 28;286(4):3065-78
references.pmid: 21062741
references.citation: Neuron. 2003 Oct 30;40(3):457-60
references.pmid: 14642270
references.citation: Biophys J. 2010 Jun 2;98(11):2722-30
references.pmid: 20513417
references.citation: Proc Natl Acad Sci U S A. 2003 Aug 5;100(16):9548-53
references.pmid: 12886013