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Tropomyosin isoforms bias actin track selection by vertebrate myosin Va

Tropomyosin (Tpm) isoforms decorate actin with distinct spatial and temporal localization patterns in cells and thus may function to sort actomyosin processes by modifying the actin track affinity for specific myosin isoforms. We examined the effect of three Tpm isoforms on the ability of myosin Va...

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Autores principales: Sckolnick, Maria, Krementsova, Elena B., Warshaw, David M., Trybus, Kathleen M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042576/
https://www.ncbi.nlm.nih.gov/pubmed/27535431
http://dx.doi.org/10.1091/mbc.E15-09-0641
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author Sckolnick, Maria
Krementsova, Elena B.
Warshaw, David M.
Trybus, Kathleen M.
author_facet Sckolnick, Maria
Krementsova, Elena B.
Warshaw, David M.
Trybus, Kathleen M.
author_sort Sckolnick, Maria
collection PubMed
description Tropomyosin (Tpm) isoforms decorate actin with distinct spatial and temporal localization patterns in cells and thus may function to sort actomyosin processes by modifying the actin track affinity for specific myosin isoforms. We examined the effect of three Tpm isoforms on the ability of myosin Va (myoVa) to engage with actin in vitro in the absence or presence of the cargo adapter melanophilin (Mlph), which links myoVa to Rab27a-melanosomes for in vivo transport. We show that both the myosin motor domain and the cargo adapter Mlph, which has an actin-binding domain that acts as a tether, are sensitive to the Tpm isoform. Actin–Tpm3.1 and actin–Tpm1.8 were equal or better tracks compared to bare actin for myoVa-HMM based on event frequency, run length, and speed. The full-length myoVa-Mlph complex showed high-frequency engagement with actin-Tpm3.1 but not with actin-Tpm1.8. Actin–Tpm4.2 excluded both myoVa-HMM and full-length myoVa-Mlph from productive interactions. Of importance, Tpm3.1 is enriched in the dendritic protrusions and cortical actin of melanocytes, where myoVa-Mlph engages in melanosome transport. These results support the hypothesis that Tpm isoforms constitute an “actin–Tpm code” that allows for spatial and temporal sorting of actomyosin function in the cell.
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spelling pubmed-50425762016-12-16 Tropomyosin isoforms bias actin track selection by vertebrate myosin Va Sckolnick, Maria Krementsova, Elena B. Warshaw, David M. Trybus, Kathleen M. Mol Biol Cell Brief Report Tropomyosin (Tpm) isoforms decorate actin with distinct spatial and temporal localization patterns in cells and thus may function to sort actomyosin processes by modifying the actin track affinity for specific myosin isoforms. We examined the effect of three Tpm isoforms on the ability of myosin Va (myoVa) to engage with actin in vitro in the absence or presence of the cargo adapter melanophilin (Mlph), which links myoVa to Rab27a-melanosomes for in vivo transport. We show that both the myosin motor domain and the cargo adapter Mlph, which has an actin-binding domain that acts as a tether, are sensitive to the Tpm isoform. Actin–Tpm3.1 and actin–Tpm1.8 were equal or better tracks compared to bare actin for myoVa-HMM based on event frequency, run length, and speed. The full-length myoVa-Mlph complex showed high-frequency engagement with actin-Tpm3.1 but not with actin-Tpm1.8. Actin–Tpm4.2 excluded both myoVa-HMM and full-length myoVa-Mlph from productive interactions. Of importance, Tpm3.1 is enriched in the dendritic protrusions and cortical actin of melanocytes, where myoVa-Mlph engages in melanosome transport. These results support the hypothesis that Tpm isoforms constitute an “actin–Tpm code” that allows for spatial and temporal sorting of actomyosin function in the cell. The American Society for Cell Biology 2016-10-01 /pmc/articles/PMC5042576/ /pubmed/27535431 http://dx.doi.org/10.1091/mbc.E15-09-0641 Text en © 2016 Sckolnick et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology.
spellingShingle Brief Report
Sckolnick, Maria
Krementsova, Elena B.
Warshaw, David M.
Trybus, Kathleen M.
Tropomyosin isoforms bias actin track selection by vertebrate myosin Va
title Tropomyosin isoforms bias actin track selection by vertebrate myosin Va
title_full Tropomyosin isoforms bias actin track selection by vertebrate myosin Va
title_fullStr Tropomyosin isoforms bias actin track selection by vertebrate myosin Va
title_full_unstemmed Tropomyosin isoforms bias actin track selection by vertebrate myosin Va
title_short Tropomyosin isoforms bias actin track selection by vertebrate myosin Va
title_sort tropomyosin isoforms bias actin track selection by vertebrate myosin va
topic Brief Report
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042576/
https://www.ncbi.nlm.nih.gov/pubmed/27535431
http://dx.doi.org/10.1091/mbc.E15-09-0641
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