Maintenance of muscle mass, fiber size, and contractile function in mice lacking the Z-disc protein myotilin.
BACKGROUND
Myofibrillar myopathies constitute a rare group of congenital neuromuscular disorders, frequently associated with mutations in Z-disc proteins such as myotilin. Myotilin location and interactions with other Z-disc proteins are clearly defined, but its role in the regulation of muscle structure and function remains unknown. The present study aims at investigating this specific role of myotilin.


METHODS
Skeletal and cardiac muscles were collected from adult mice with a targeted deletion of myotilin (myo(-/-)) and wild-type animals (myo(+/+)).


CONCLUSIONS
Similar skeletal and cardiac muscle weights were observed in myo(-/-) and myo(+/+) mice. At the muscle cell level, the size and force production of single membrane permeabilized fibers were identical between myo(-/-) and myo(+/+) rodents. Thus, myotilin does not have a significant influence on muscle mass, muscle fiber size, or regulation of muscle contraction. Alternatively, compensatory over-expressions of other elements including proteins from the same subfamily, or Z-disc proteins such as telethonin, or intermediate filaments may compensate for the lack of myotilin.
Ochala
Julien
J
Department of Clinical Neurophysiology, Uppsala University Hospital, Sweden. julien.ochala@neuro.uu.se
Carpén
Olli
O
Larsson
Lars
L
D000818:Animals; D064211:Connectin; D003598:Cytoskeletal Proteins / Q000235:genetics; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins; D008954:Models, Biological; D009119:Muscle Contraction; D018485:Muscle Fibers, Skeletal / Q000502:physiology / Q000648:ultrastructure; D009124:Muscle Proteins / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology*; D009135:Muscular Diseases / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D009154:Mutation; D009200:Myocardial Contraction; D009210:Myofibrils / Q000473:pathology / Q000502:physiology; D009929:Organ Size
D064211:Connectin; D003598:Cytoskeletal Proteins; C577290:MYOT protein, human; D008840:Microfilament Proteins; D009124:Muscle Proteins; C503771:Myot protein, mouse