Cargando…
Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro
Muscle contraction depends on the cyclical interaction of myosin and actin filaments. Therefore, it is important to understand the mechanisms of polymerization and depolymerization of muscle myosins. Muscle myosin 2 monomers exist in two states: one with a folded tail that interacts with the heads (...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
National Academy of Sciences
2020
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354935/ https://www.ncbi.nlm.nih.gov/pubmed/32571956 http://dx.doi.org/10.1073/pnas.2001892117 |
_version_ | 1783558188918898688 |
---|---|
author | Liu, Xiong Shu, Shi Korn, Edward D. |
author_facet | Liu, Xiong Shu, Shi Korn, Edward D. |
author_sort | Liu, Xiong |
collection | PubMed |
description | Muscle contraction depends on the cyclical interaction of myosin and actin filaments. Therefore, it is important to understand the mechanisms of polymerization and depolymerization of muscle myosins. Muscle myosin 2 monomers exist in two states: one with a folded tail that interacts with the heads (10S) and one with an unfolded tail (6S). It has been thought that only unfolded monomers assemble into bipolar and side-polar (smooth muscle myosin) filaments. We now show by electron microscopy that, after 4 s of polymerization in vitro in both the presence (smooth muscle myosin) and absence of ATP, skeletal, cardiac, and smooth muscle myosins form tail-folded monomers without tail–head interaction, tail-folded antiparallel dimers, tail-folded antiparallel tetramers, unfolded bipolar tetramers, and small filaments. After 4 h, the myosins form thick bipolar and, for smooth muscle myosin, side-polar filaments. Nonphosphorylated smooth muscle myosin polymerizes in the presence of ATP but with a higher critical concentration than in the absence of ATP and forms only bipolar filaments with bare zones. Partial depolymerization in vitro of nonphosphorylated smooth muscle myosin filaments by the addition of MgATP is the reverse of polymerization. |
format | Online Article Text |
id | pubmed-7354935 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | National Academy of Sciences |
record_format | MEDLINE/PubMed |
spelling | pubmed-73549352020-07-24 Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro Liu, Xiong Shu, Shi Korn, Edward D. Proc Natl Acad Sci U S A Biological Sciences Muscle contraction depends on the cyclical interaction of myosin and actin filaments. Therefore, it is important to understand the mechanisms of polymerization and depolymerization of muscle myosins. Muscle myosin 2 monomers exist in two states: one with a folded tail that interacts with the heads (10S) and one with an unfolded tail (6S). It has been thought that only unfolded monomers assemble into bipolar and side-polar (smooth muscle myosin) filaments. We now show by electron microscopy that, after 4 s of polymerization in vitro in both the presence (smooth muscle myosin) and absence of ATP, skeletal, cardiac, and smooth muscle myosins form tail-folded monomers without tail–head interaction, tail-folded antiparallel dimers, tail-folded antiparallel tetramers, unfolded bipolar tetramers, and small filaments. After 4 h, the myosins form thick bipolar and, for smooth muscle myosin, side-polar filaments. Nonphosphorylated smooth muscle myosin polymerizes in the presence of ATP but with a higher critical concentration than in the absence of ATP and forms only bipolar filaments with bare zones. Partial depolymerization in vitro of nonphosphorylated smooth muscle myosin filaments by the addition of MgATP is the reverse of polymerization. National Academy of Sciences 2020-07-07 2020-06-22 /pmc/articles/PMC7354935/ /pubmed/32571956 http://dx.doi.org/10.1073/pnas.2001892117 Text en Copyright © 2020 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/ https://creativecommons.org/licenses/by-nc-nd/4.0/This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) . |
spellingShingle | Biological Sciences Liu, Xiong Shu, Shi Korn, Edward D. Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro |
title | Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro |
title_full | Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro |
title_fullStr | Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro |
title_full_unstemmed | Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro |
title_short | Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro |
title_sort | muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro |
topic | Biological Sciences |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354935/ https://www.ncbi.nlm.nih.gov/pubmed/32571956 http://dx.doi.org/10.1073/pnas.2001892117 |
work_keys_str_mv | AT liuxiong musclemyosinsformfoldedmonomersdimersandtetramersduringfilamentpolymerizationinvitro AT shushi musclemyosinsformfoldedmonomersdimersandtetramersduringfilamentpolymerizationinvitro AT kornedwardd musclemyosinsformfoldedmonomersdimersandtetramersduringfilamentpolymerizationinvitro |