Journal article
The Arabidopsis Microtubule-Associated Protein AtMAP65-1: Molecular Analysis of Its Microtubule Bundling Activity
The Plant cell, Vol.16(8), pp.2035-2047
08/2004
Handle:
https://hdl.handle.net/2376/106311
PMCID: PMC519196
PMID: 15273298
Abstract
The 65-kD microtubule-associated protein (MAP65) family is a family of plant microtubule-bundling proteins. Functional analysis is complicated by the heterogeneity within this family: there are nine MAP65 genes in
Arabidopsis thaliana
,
AtMAP65-1
to
AtMAP65-9
. To begin the functional dissection of the Arabidopsis MAP65 proteins, we have concentrated on a single isoform, AtMAP65-1, and examined its effect on the dynamics of mammalian microtubules. We show that recombinant AtMAP65-1 does not promote polymerization and does not stabilize microtubules against cold-induced microtubule depolymerization. However, we show that it does induce microtubule bundling in vitro and that this protein forms 25-nm cross-bridges between microtubules. We further demonstrate that the microtubule binding region resides in the C-terminal half of the protein and that Ala409 and Ala420 are essential for the interaction with microtubules. Ala420 is a conserved amino acid in the AtMAP65 family and is mutated to Val in the cytokinesis-defective mutant
pleiade-4
of the
AtMAP65-3
/
PLEIADE
gene. We show that AtMAP65-1 can form dimers and that a region in the N terminus is responsible for this activity. Neither the microtubule binding region nor the dimerization region alone could induce microtubule bundling, strongly suggesting that dimerization is necessary to produce the microtubule cross-bridges. In vivo, AtMAP65-1 is ubiquitously expressed both during the cell cycle and in all plant organs and tissues with the exception of anthers and petals. Moreover, using an antiserum raised to AtMAP65-1, we show that AtMAP65-1 binds microtubules at specific stages of the cell cycle.
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Details
- Title
- The Arabidopsis Microtubule-Associated Protein AtMAP65-1: Molecular Analysis of Its Microtubule Bundling Activity
- Creators
- Andrei P Smertenko - Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, United KingdomHsin-Yu Chang - Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, United KingdomVera Wagner - Institute of Applied Genetics and Cell Biology, BOKU, University of Natural Resources and Applied Life Sciences, Muthgasse 18 A-1190 Vienna, AustriaDespina Kaloriti - Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, United KingdomStepan Fenyk - Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, United KingdomSeiji Sonobe - Himeji Institute of Technology, Faculty of Science, Hyogo, JapanClive Lloyd - Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United KingdomMarie-Theres Hauser - Institute of Applied Genetics and Cell Biology, BOKU, University of Natural Resources and Applied Life Sciences, Muthgasse 18 A-1190 Vienna, AustriaPatrick J Hussey - Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, United Kingdom
- Publication Details
- The Plant cell, Vol.16(8), pp.2035-2047
- Academic Unit
- Biological Chemistry, Institute of
- Publisher
- American Society of Plant Biologists
- Identifiers
- 99900546659801842
- Language
- English
- Resource Type
- Journal article