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Structural and mechanical roles of the intermediate filament syncoilin in skeletal muscle: implications for muscular dystrophy
Author(s) -
Gokhin David Samuel,
Bang MarieLouise,
Zhang Jianlin,
Bremner Shan N.,
Chen Ju,
Lieber Richard L.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.962.1
Subject(s) - isometric exercise , skeletal muscle , muscular dystrophy , anatomy , muscle contraction , myosin , eccentric , chemistry , medicine , biology , biophysics , physics , quantum mechanics
The muscle‐specific intermediate filament syncoilin has been implicated as a contributor to muscular dystrophy because it interacts with α‐dystrobrevin and desmin, both of which are components of the skeletal muscle lateral force transmission network. To probe the functional roles of syncoilin, a syncoilin‐knockout (SKO) mouse strain was developed, and the structural and mechanical properties of SKO muscle were compared to wild‐type (WT) muscle. Muscle fiber cross‐sectional area was identical in SKO and WT muscles, and SKO muscle showed no signs of pathological disruption. Functionally, maximal isometric stress was significantly reduced in SKO muscle (240±22 kPa) compared to WT muscle (304±13 kPa), indicating that syncoilin deficiency disrupts active force generation. However, both SKO and WT muscles exhibited identical vulnerability to eccentric contraction‐induced muscle injury. Passive mechanical testing of single muscle fibers revealed no significant reduction in Young's modulus in SKO fibers (68±6 kPa) relative to WT fibers (75±5 kPa). Therefore, syncoilin deficiency results in a mild phenotypic change in skeletal muscle, although the reduced maximal isometric stress observed in SKO muscle may predispose the muscle to a dystrophic condition. These data suggest a subtle role of syncoilin in muscle force transmission pathways. Supported by NIH and the Department of Veterans Affairs