synemin; desmuslin (SYNM, DMN, KIAA0353, SYN)
Jump to navigation
Jump to search
Function
- intermediate filament type-6
- role within the muscle cell cytoskeleton
- forms heteropolymeric intermediate filaments (IFs) with desmin &/or vimentin
- via its interaction with cytoskeletal proteins:
- alpha-dystrobrevin
- dystrophin
- talin-1
- utrophin
- vinculin, is able to link these heteropolymeric IFs to adherens-type junctions, such as to the costameres, neuromuscular junctions, & myotendinous junctions within striated muscle cells
- interacts with GFAP & VIM (putative)
- isoform 1 interacts with TLN1 & VCL
- isoform 2 interacts with DES & DTNA
- isoform 1 & isoform 2 interact with DMD & UTRN
Structure
- belongs to the intermediate filament family
Compartment
- 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, & another in which it interacts with both DTNA & DES at the costamere
Alternative splicing
named isoforms=3
Expression
- isoform 2 is strongly detected in adult heart, fetal skeletal muscles & fetal heart
- isoform 1 is weakly detected in fetal heart & also in fetal skeletal muscle
- isoform 1 & isoform 2 are detected in adult bladder (at protein level)
- the mRNA is predominantly expressed in heart & muscle with some expression in brain which may be due to tissue-specific isoforms
- in lens
- first detected at 16 weeks when expression is weakly & uniformly distributed
- subsequently, expression becomes much stronger in the epithelium of the anterior part at 25 weeks & later
- in retina
- weakly expressed at 15 weeks in the nerve fiber layer & ganglion cell layer
- from 25 weeks onwards, much stronger expression is observed in the endfeet of Mueller cells, the nerve fiber layer, & ganglion cell layer
- much lower expression is observed in a minor subpopulation of cells in the inner cell layer
- at 30 & 36 weeks, expression remains in the neural retina, & subsequently becomes stronger in the nerve fiber layer, ganglion cell layer, & inner cell layer & is decreased in Mueller cells
- at 36 weeks, also expressed at the external border of the outer nuclear layer (at protein level)