Journal article
Two Protein 4.1 Domains Essential for Mitotic Spindle and Aster Microtubule Dynamics and Organization in Vitro
The Journal of biological chemistry, Vol.279(26), pp.27591-27598
06/25/2004
DOI: 10.1074/jbc.M402813200
PMID: 15102852
Abstract
Multifunctional structural proteins belonging to the 4.1 family are components of nuclei, spindles, and centrosomes in vertebrate cells. Here we report that 4.1 is critical for spindle assembly and the formation of centrosome-nucleated and motor-dependent self-organized microtubule asters in metaphase-arrested Xenopus egg extracts. Immunodepletion of 4.1 disrupted microtubule arrays and mislocalized the spindle pole protein NuMA. Remarkably, assembly was completely rescued by supplementation with a recombinant 4.1R isoform. We identified two 4.1 domains critical for its function in microtubule polymerization and organization utilizing dominant negative peptides. The 4.1 spectrin-actin binding domain or NuMA binding C-terminal domain peptides caused morphologically disorganized structures. Control peptides with low homology or variant spectrin-actin binding domain peptides that were incapable of binding actin had no deleterious effects. Unexpectedly, the addition of C-terminal domain peptides with reduced NuMA binding caused severe microtubule destabilization in extracts, dramatically inhibiting aster and spindle assembly and also depolymerizing preformed structures. However, the mutant C-terminal peptides did not directly inhibit or destabilize microtubule polymerization from pure tubulin in a microtubule pelleting assay. Our data showing that 4.1 is a crucial factor for assembly and maintenance of mitotic spindles and self-organized and centrosome-nucleated microtubule asters indicates that 4.1 is involved in regulating both microtubule dynamics and organization. These investigations underscore an important functional context for protein 4.1 in microtubule morphogenesis and highlight a previously unappreciated role for 4.1 in cell division.
Details
- Title: Subtitle
- Two Protein 4.1 Domains Essential for Mitotic Spindle and Aster Microtubule Dynamics and Organization in Vitro
- Creators
- Sharon Wald Krauss - Lawrence Berkeley National Laboratory, Life Sciences Division, University of California, Berkeley, 94720 CaliforniaGloria Lee - Lawrence Berkeley National Laboratory, Life Sciences Division, University of California, Berkeley, 94720 CaliforniaJoel Anne Chasis - Lawrence Berkeley National Laboratory, Life Sciences Division, University of California, Berkeley, 94720 CaliforniaNarla Mohandas - New York Blood Center, New York, New York 10021Rebecca Heald - Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.279(26), pp.27591-27598
- Publisher
- Elsevier Inc
- DOI
- 10.1074/jbc.M402813200
- PMID
- 15102852
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Language
- English
- Date published
- 06/25/2004
- Academic Unit
- Iowa Neuroscience Institute; Immunology; Internal Medicine
- Record Identifier
- 9984070507302771
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