Cargando…
Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin
Ena/VASP tetramers are processive actin elongation factors that localize to diverse F-actin networks composed of filaments bundled by different cross-linking proteins, such as filopodia (fascin), lamellipodia (fimbrin), and stress fibers (α-actinin). Previously, we found that Ena takes approximately...
Autores principales: | , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The American Society for Cell Biology
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6589784/ https://www.ncbi.nlm.nih.gov/pubmed/30601697 http://dx.doi.org/10.1091/mbc.E18-08-0500 |
_version_ | 1783429438758715392 |
---|---|
author | Harker, Alyssa J. Katkar, Harshwardhan H. Bidone, Tamara C. Aydin, Fikret Voth, Gregory A. Applewhite, Derek A. Kovar, David R. |
author_facet | Harker, Alyssa J. Katkar, Harshwardhan H. Bidone, Tamara C. Aydin, Fikret Voth, Gregory A. Applewhite, Derek A. Kovar, David R. |
author_sort | Harker, Alyssa J. |
collection | PubMed |
description | Ena/VASP tetramers are processive actin elongation factors that localize to diverse F-actin networks composed of filaments bundled by different cross-linking proteins, such as filopodia (fascin), lamellipodia (fimbrin), and stress fibers (α-actinin). Previously, we found that Ena takes approximately threefold longer processive runs on trailing barbed ends of fascin-bundled F-actin. Here, we used single-molecule TIRFM (total internal reflection fluorescence microscopy) and developed a kinetic model to further dissect Ena/VASP’s processive mechanism on bundled filaments. We discovered that Ena’s enhanced processivity on trailing barbed ends is specific to fascin bundles, with no enhancement on fimbrin or α-actinin bundles. Notably, Ena/VASP’s processive run length increases with the number of both fascin-bundled filaments and Ena “arms,” revealing avidity facilitates enhanced processivity. Consistently, Ena tetramers form more filopodia than mutant dimer and trimers in Drosophila culture cells. Moreover, enhanced processivity on trailing barbed ends of fascin-bundled filaments is an evolutionarily conserved property of Ena/VASP homologues, including human VASP and Caenorhabditis elegans UNC-34. These results demonstrate that Ena tetramers are tailored for enhanced processivity on fascin bundles and that avidity of multiple arms associating with multiple filaments is critical for this process. Furthermore, we discovered a novel regulatory process whereby bundle size and bundling protein specificity control activities of a processive assembly factor. |
format | Online Article Text |
id | pubmed-6589784 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | The American Society for Cell Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-65897842019-07-02 Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin Harker, Alyssa J. Katkar, Harshwardhan H. Bidone, Tamara C. Aydin, Fikret Voth, Gregory A. Applewhite, Derek A. Kovar, David R. Mol Biol Cell Articles Ena/VASP tetramers are processive actin elongation factors that localize to diverse F-actin networks composed of filaments bundled by different cross-linking proteins, such as filopodia (fascin), lamellipodia (fimbrin), and stress fibers (α-actinin). Previously, we found that Ena takes approximately threefold longer processive runs on trailing barbed ends of fascin-bundled F-actin. Here, we used single-molecule TIRFM (total internal reflection fluorescence microscopy) and developed a kinetic model to further dissect Ena/VASP’s processive mechanism on bundled filaments. We discovered that Ena’s enhanced processivity on trailing barbed ends is specific to fascin bundles, with no enhancement on fimbrin or α-actinin bundles. Notably, Ena/VASP’s processive run length increases with the number of both fascin-bundled filaments and Ena “arms,” revealing avidity facilitates enhanced processivity. Consistently, Ena tetramers form more filopodia than mutant dimer and trimers in Drosophila culture cells. Moreover, enhanced processivity on trailing barbed ends of fascin-bundled filaments is an evolutionarily conserved property of Ena/VASP homologues, including human VASP and Caenorhabditis elegans UNC-34. These results demonstrate that Ena tetramers are tailored for enhanced processivity on fascin bundles and that avidity of multiple arms associating with multiple filaments is critical for this process. Furthermore, we discovered a novel regulatory process whereby bundle size and bundling protein specificity control activities of a processive assembly factor. The American Society for Cell Biology 2019-03-21 /pmc/articles/PMC6589784/ /pubmed/30601697 http://dx.doi.org/10.1091/mbc.E18-08-0500 Text en © 2019 Harker et al. “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology. http://creativecommons.org/licenses/by-nc-sa/3.0 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. |
spellingShingle | Articles Harker, Alyssa J. Katkar, Harshwardhan H. Bidone, Tamara C. Aydin, Fikret Voth, Gregory A. Applewhite, Derek A. Kovar, David R. Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin |
title | Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin |
title_full | Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin |
title_fullStr | Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin |
title_full_unstemmed | Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin |
title_short | Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin |
title_sort | ena/vasp processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6589784/ https://www.ncbi.nlm.nih.gov/pubmed/30601697 http://dx.doi.org/10.1091/mbc.E18-08-0500 |
work_keys_str_mv | AT harkeralyssaj enavaspprocessiveelongationismodulatedbyavidityonactinfilamentsbundledbythefilopodiacrosslinkerfascin AT katkarharshwardhanh enavaspprocessiveelongationismodulatedbyavidityonactinfilamentsbundledbythefilopodiacrosslinkerfascin AT bidonetamarac enavaspprocessiveelongationismodulatedbyavidityonactinfilamentsbundledbythefilopodiacrosslinkerfascin AT aydinfikret enavaspprocessiveelongationismodulatedbyavidityonactinfilamentsbundledbythefilopodiacrosslinkerfascin AT vothgregorya enavaspprocessiveelongationismodulatedbyavidityonactinfilamentsbundledbythefilopodiacrosslinkerfascin AT applewhitedereka enavaspprocessiveelongationismodulatedbyavidityonactinfilamentsbundledbythefilopodiacrosslinkerfascin AT kovardavidr enavaspprocessiveelongationismodulatedbyavidityonactinfilamentsbundledbythefilopodiacrosslinkerfascin |