title: The Inner Centromere Protein (INCENP) Coil Is a Single α-Helix (SAH) Domain That Binds Directly to Microtubules and Is Important for Chromosome Passenger Complex (CPC) Localization and Function in Mitosis.
abstract: The chromosome passenger complex (CPC) is a master regulator of mitosis. Inner centromere protein (INCENP) acts as a scaffold regulating CPC localization and activity. During early mitosis, the N-terminal region of INCENP forms a three-helix bundle with Survivin and Borealin, directing the CPC to the inner centromere where it plays essential roles in chromosome alignment and the spindle assembly checkpoint. The C-terminal IN box region of INCENP is responsible for binding and activating Aurora B kinase. The central region of INCENP has been proposed to comprise a coiled coil domain acting as a spacer between the N- and C-terminal domains that is involved in microtubule binding and regulation of the spindle checkpoint. Here we show that the central region (213 residues) of chicken INCENP is not a coiled coil but a ∼ 32-nm-long single α-helix (SAH) domain. The N-terminal half of this domain directly binds to microtubules in vitro. By analogy with previous studies of myosin 10, our data suggest that the INCENP SAH might stretch up to ∼ 80 nm under physiological forces. Thus, the INCENP SAH could act as a flexible "dog leash," allowing Aurora B to phosphorylate dynamic substrates localized in the outer kinetochore while at the same time being stably anchored to the heterochromatin of the inner centromere. Furthermore, by achieving this flexibility via an SAH domain, the CPC avoids a need for dimerization (required for coiled coil formation), which would greatly complicate regulation of the proximity-induced trans-phosphorylation that is critical for Aurora B activation.
authors.affiliation: From The Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, United Kingdom and kumiko.samejima@ed.ac.uk.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Samejima
authors.affiliation: From The Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, United Kingdom and.
authors.forename: Melpomeni
authors.initials: M
authors.lastname: Platani
authors.affiliation: The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Marcin
authors.initials: M
authors.lastname: Wolny
authors.affiliation: From The Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, United Kingdom and.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ogawa
authors.affiliation: From The Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, United Kingdom and.
authors.forename: Giulia
authors.initials: G
authors.lastname: Vargiu
authors.affiliation: The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Knight
authors.affiliation: The Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom M.Peckham@leeds.ac.uk.
authors.forename: Michelle
authors.initials: M
authors.lastname: Peckham
authors.affiliation: From The Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, United Kingdom and bill.earnshaw@ed.ac.uk.
authors.forename: William C
authors.initials: WC
authors.lastname: Earnshaw
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D064107:Aurora Kinase B / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D002645:Chickens; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis; D008954:Models, Biological; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D050505:Mutant Proteins; D064107:Aurora Kinase B
keywords: CPC; INCENP; centromere; chromosome passenger complex; coiled coil; microtubule; mitosis; mutant; protein structure; single α-helix