Open AccessSmooth muscle function and myosin polymerization
Author(s) -
Pasquale Chitano,
Lu Wang,
Gabrielle Y. Y. Tin,
Mitsuo Ikebe,
Peter D. Paré,
Chun Y. Seow
Publication year - 2017
Publication title -
journal of cell science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.384
H-Index - 278
eISSN - 1477-9137
pISSN - 0021-9533
DOI - 10.1242/jcs.202812
Subject(s) - myosin , biology , biophysics , contractility , isometric exercise , muscle contraction , actin , meromyosin , protein filament , contraction (grammar) , myosin head , phosphorylation , myofilament , myosin light chain kinase , anatomy , microbiology and biotechnology , biochemistry , endocrinology , physiology
Smooth muscle is able to function over a much broader length range than striated muscle. The ability to maintain contractility after a large length change is thought to be due to an adaptive process involving restructuring of the contractile apparatus to maximize overlap between the contractile filaments. The molecular mechanism for the length-adaptive behavior is largely unknown. In smooth muscle adapted to different lengths we quantified myosin monomers, basal and activation-induced myosin light chain (MLC) phosphorylation, shortening-velocity, power-output and active force. The muscle was able to generate a constant maximal force over a 2-fold length range when it was allowed to go through isometric contraction/relaxation cycles after each length change (length adaptation). In the relaxed state myosin monomer concentration and basal MLC phosphorylation decreased linearly, while in the activated state activation-induced MLC phosphorylation and shortening-velocity/power-output increased linearly with muscle length. The results suggest that recruitment of myosin monomers and oligomers into the actin filament lattice (where they form force-generating filaments) occurs during muscle adaptation to longer length with the opposite occurring during adaptation to shorter length.