Synemin

Synemin is a type III intermediate filament protein found in various tissues throughout the body. Also known as desmuslin, it was first identified in smooth muscle cells and later discovered in other cell types including skeletal and cardiac muscle, as well as in glial cells. Synemin forms part of the cytoskeleton, providing structural support to cells and helping maintain their shape.

The protein has a molecular weight of approximately 150-180 kDa and contains an alpha-helical rod domain characteristic of intermediate filament proteins. Synemin can co-assemble with other intermediate filament proteins such as desmin, vimentin, and GFAP, forming heteropolymeric filaments that contribute to cellular integrity.

Research has shown that synemin plays a crucial role in connecting the cytoskeleton to the extracellular matrix through interactions with integrins and other adhesion molecules. This connection is important for cell signaling, mechanotransduction, and maintaining tissue architecture. In muscle cells, synemin helps transmit mechanical forces from the contractile apparatus to the cell membrane.

Mutations or altered expression of synemin have been associated with certain pathological conditions, including muscular dystrophies and some cancers, highlighting its importance in maintaining cellular homeostasis.