Structure-Function Relationship of the Bik1-Bim1 Complex

Marcel M Stangier; Anil Kumar; Xiuzhen Chen; Ana-Maria Farcas; Yves Barral; Michel O Steinmetz

doi:10.1016/j.str.2018.03.003

Structure-Function Relationship of the Bik1-Bim1 Complex

Structure. 2018 Apr 3;26(4):607-618.e4. doi: 10.1016/j.str.2018.03.003. Epub 2018 Mar 22.

Authors

Marcel M Stangier¹, Anil Kumar¹, Xiuzhen Chen², Ana-Maria Farcas², Yves Barral², Michel O Steinmetz³

Affiliations

¹ Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
² Institute of Biochemistry, ETH Zürich, 8049 Zürich, Switzerland.
³ Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland; University of Basel, Biozentrum, 4056 Basel, Switzerland. Electronic address: michel.steinmetz@psi.ch.

PMID: 29576319
DOI: 10.1016/j.str.2018.03.003

Abstract

In budding yeast, the microtubule plus-end tracking proteins Bik1 (CLIP-170) and Bim1 (EB1) form a complex that interacts with partners involved in spindle positioning, including Stu2 and Kar9. Here, we show that the CAP-Gly and coiled-coil domains of Bik1 interact with the C-terminal ETF peptide of Bim1 and the C-terminal tail region of Stu2, respectively. The crystal structures of the CAP-Gly domain of Bik1 (Bik1CG) alone and in complex with an ETF peptide revealed unique, functionally relevant CAP-Gly elements, establishing Bik1CG as a specific C-terminal phenylalanine recognition domain. Unlike the mammalian CLIP-170-EB1 complex, Bik1-Bim1 forms ternary complexes with the EB1-binding motifs SxIP and LxxPTPh, which are present in diverse proteins, including Kar9. Perturbation of the Bik1-Bim1 interaction in vivo affected Bik1 localization and astral microtubule length. Our results provide insight into the role of the Bik1-Bim1 interaction for cell division, and demonstrate that the CLIP-170-EB1 module is evolutionarily flexible.

Keywords: CAP-Gly domains; X-ray crystallography; microtubule plus-end tracking proteins; protein-protein interactions; structure-function relationship.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Binding Sites
Cell Cycle Proteins / chemistry*
Cell Cycle Proteins / genetics
Cell Cycle Proteins / metabolism
Cell Division
Cloning, Molecular
Crystallography, X-Ray
Escherichia coli / genetics
Escherichia coli / metabolism
Evolution, Molecular
Gene Expression
Genetic Vectors / chemistry
Genetic Vectors / metabolism
Microtubule Proteins / chemistry*
Microtubule Proteins / genetics
Microtubule Proteins / metabolism
Microtubule-Associated Proteins / chemistry*
Microtubule-Associated Proteins / genetics
Microtubule-Associated Proteins / metabolism
Microtubules / chemistry
Microtubules / ultrastructure
Models, Molecular
Nuclear Proteins / chemistry*
Nuclear Proteins / genetics
Nuclear Proteins / metabolism
Protein Binding
Protein Conformation, alpha-Helical
Protein Conformation, beta-Strand
Protein Interaction Domains and Motifs
Recombinant Proteins / chemistry
Recombinant Proteins / genetics
Recombinant Proteins / metabolism
Saccharomyces cerevisiae / chemistry*
Saccharomyces cerevisiae / metabolism
Saccharomyces cerevisiae / ultrastructure
Saccharomyces cerevisiae Proteins / chemistry*
Saccharomyces cerevisiae Proteins / genetics
Saccharomyces cerevisiae Proteins / metabolism
Sequence Alignment
Sequence Homology, Amino Acid
Spindle Apparatus / chemistry
Spindle Apparatus / ultrastructure
Structure-Activity Relationship

Substances

BIM1 protein, S cerevisiae
Bik1 protein, S cerevisiae
Cell Cycle Proteins
KAR9 protein, S cerevisiae
Microtubule Proteins
Microtubule-Associated Proteins
Nuclear Proteins
Recombinant Proteins
STU2 protein, S cerevisiae
Saccharomyces cerevisiae Proteins