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.
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.