Type-VI intermediate filament (IF) which plays an important cytoskeletal role within the muscle cell cytoskeleton. It forms heteromeric IFs with desmin and/or vimentin, and via its interaction with cytoskeletal proteins alpha-dystrobrevin, dystrophin, talin-1, utrophin and vinculin, is able to link these heteromeric IFs to adherens-type junctions, such as to the costameres, neuromuscular junctions, and myotendinous junctions within striated muscle cells.
Subcellular locations: Cytoplasm, Cytoskeleton, Cell junction, Adherens junction
There are at least two distinct SYNM subpopulations, one in which SYMN interacts with DES within the Z-lines, and another in which it interacts with both DTNA and DES at the costamere.
Isoform 2 is strongly detected in adult heart, fetal skeletal muscles and fetal heart. Isoform 1 is weakly detected in fetal heart and also in fetal skeletal muscle. Isoform 1 and isoform 2 are detected in adult bladder (at protein level). The mRNA is predominantly expressed in heart and muscle with some expression in brain which may be due to tissue-specific isoforms.