title: Mal3, the Schizosaccharomyces pombe homolog of EB1, changes the microtubule lattice.
abstract: In vitro studies of pure tubulin have suggested that tubulin heterodimers in cells assemble into B-lattice microtubules, where the 8-nm dimers in adjacent protofilaments are staggered by 0.9 nm. This arrangement requires the tube to close by forming a seam with an A-lattice, in which the protofilaments are staggered by 4.9 nm. Here we show that Mal3, an EB1 family tip-tracking protein, drives tubulin to assemble in vitro into exclusively 13-protofilament microtubules with a high proportion of A-lattice protofilament contacts. We present a three-dimensional cryo-EM reconstruction of a purely A-lattice microtubule decorated with Mal3, in which Mal3 occupies the groove between protofilaments and associates closely with one tubulin monomer. We propose that Mal3 promotes assembly by binding to freshly formed tubulin polymer and particularly favors any with A-lattice arrangement. These results reopen the question of microtubule structure in cells.
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
authors.forename: Amédée
authors.initials: A
authors.lastname: des Georges
authors.forename: Miho
authors.initials: M
authors.lastname: Katsuki
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Drummond
authors.forename: Michael
authors.initials: M
authors.lastname: Osei
authors.forename: Robert A
authors.initials: RA
authors.lastname: Cross
authors.forename: Linda A
authors.initials: LA
authors.lastname: Amos
mesh_terms: D000595:Amino Acid Sequence; D020285:Cryoelectron Microscopy; D017353:Gene Deletion; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D008958:Models, Molecular; D011485:Protein Binding; D012568:Schizosaccharomyces / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: C108851:Mal3 protein, S pombe; D008869:Microtubule-Associated Proteins; D029702:Schizosaccharomyces pombe Proteins
references.citation: EMBO J. 2005 Jan 26;24(2):261-9
references.pmid: 15616574
references.citation: J Struct Biol. 1996 Jan-Feb;116(1):9-16
references.pmid: 8742717
references.citation: J Biol Chem. 1985 Aug 25;260(18):10208-16
references.pmid: 3894367
references.citation: Curr Opin Cell Biol. 2005 Feb;17(1):47-54
references.pmid: 15661518
references.citation: Nature. 2005 Jun 16;435(7044):895-7
references.pmid: 15959501
references.citation: Nat Cell Biol. 2000 Jun;2(6):365-70
references.pmid: 10854328
references.citation: Proc Natl Acad Sci U S A. 1993 Mar 1;90(5):1671-5
references.pmid: 8446580
references.citation: Nature. 1989 Apr 20;338(6217):662-4
references.pmid: 2649796
references.citation: Nature. 2007 Dec 13;450(7172):1100-5
references.pmid: 18059460
references.citation: Cell. 2006 Dec 29;127(7):1415-24
references.pmid: 17190604
references.citation: Nature. 2004 Mar 11;428(6979):198-202
references.pmid: 15014504
references.citation: J Biochem. 2003 Sep;134(3):321-6
references.pmid: 14561716
references.citation: J Cell Biol. 1994 Dec;127(6 Pt 2):1965-71
references.pmid: 7806574
references.citation: Mol Cell. 2004 Jun 18;14(6):833-9
references.pmid: 15200960
references.citation: J Cell Biol. 1995 Jun;129(5):1311-28
references.pmid: 7775577
references.citation: Nature. 1998 Jan 8;391(6663):199-203
references.pmid: 9428769
references.citation: J Cell Biol. 1997 Nov 3;139(3):717-28
references.pmid: 9348288
references.citation: J Biol Chem. 1986 Jul 5;261(19):9070-6
references.pmid: 3522582
references.citation: Mol Biol Cell. 2000 May;11(5):1887-903
references.pmid: 10793159
references.citation: Curr Opin Cell Biol. 2008 Feb;20(1):71-6
references.pmid: 18226514
references.citation: Mol Biol Cell. 2008 Jan;19(1):207-15
references.pmid: 17978090
references.citation: J Cell Biol. 2002 Jan 21;156(2):349-59
references.pmid: 11807097
references.citation: J Cell Biol. 1986 Mar;102(3):1118-26
references.pmid: 3512580
references.citation: Cell. 2001 May 18;105(4):421-4
references.pmid: 11371339
references.citation: Cell Mol Life Sci. 2007 Feb;64(3):307-17
references.pmid: 17221167
references.citation: Annu Rev Cell Dev Biol. 1997;13:83-117
references.pmid: 9442869
references.citation: J Cell Sci. 1974 May;14(3):523-49
references.pmid: 4830832
references.citation: Genome Res. 1997 Dec;7(12):1174-83
references.pmid: 9414323
references.citation: J Cell Biol. 1988 Oct;107(4):1437-48
references.pmid: 3170635
references.citation: J Mol Biol. 1999 Mar 26;287(2):287-92
references.pmid: 10080892
references.citation: Nat Cell Biol. 2008 Apr;10(4):415-21
references.pmid: 18364701
references.citation: Nature. 2005 Jun 16;435(7044):911-5
references.pmid: 15959508
references.citation: J Biol Chem. 2005 Apr 1;280(13):12299-304
references.pmid: 15665379
references.citation: Biochemistry. 2008 Jan 15;47(2):779-86
references.pmid: 18081319
references.citation: Biochemistry. 1993 Aug 31;32(34):8823-35
references.pmid: 8364030