Identification of a novel microtubule-binding domain in microtubule-associated protein 1A (MAP1A)
Several microtubule-associated proteins (MAPs) have been shown to bind to microtubules via short sequences with repeated amino acids motifs. A microtubule-binding domain has hitherto not been defined for the adult brain microtubule-associated protein 1A (MAP1A). We have searched for a microtubule-bi...
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Published in | Journal of cell science Vol. 107; no. 3; pp. 661 - 672 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Company of Biologists
01.03.1994
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Subjects | |
Online Access | Get full text |
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Summary: | Several microtubule-associated proteins (MAPs) have been shown to bind to microtubules via short sequences with repeated amino acids motifs. A microtubule-binding domain has hitherto not been defined for the adult brain microtubule-associated protein 1A (MAP1A). We have searched for a microtubule-binding domain by expressing different protein regions of MAP1A in cultured cell lines using cDNA constructs. One construct included an area with homology to the microtubule-binding domain of MAP1B (Noble et al. (1989) J. Cell Biol. 109, 437-448), but this did not bind to microtubules in transfected cells. Further investigation of other areas of MAP1A revealed a protein domain, capable of autonomously binding to microtubules, which bears no homology to any previously described microtubule-binding sequence. This MAP1A domain is rich in charged amino acids, as are other mammalian microtubule-binding domains, but unlike them has no identifiable sequence repeats. Whereas all previously described mammalian microtubule-binding domains are basic, this novel microtubule-binding domain of MAP1A is acidic. The expression of this polypeptide in cultured cell lines led to a rearrangement of the microtubules in a pattern distinct from that produced by MAP2 or tau, and increased their resistance to treatment with the microtubule depolymerising agent nocodazole. When the MAP1A microtubule-binding domain was co-expressed in cultured cell lines together with MAP2c, the MAP1A microtubule-binding domain was able to bind to the MAP2c-induced microtubule bundles. These results suggest that different microtubule-binding sequences have a common ability to stabilise microtubules but differ in their influence on microtubule arrangement in the cell. This may be significant in neurons, where microtubule-associated proteins with different microtubule-binding sequences are expressed in different cell compartments and at different times during development. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0021-9533 1477-9137 |
DOI: | 10.1242/jcs.107.3.661 |