Synemin

Synemin, intermediate filament protein
Identifiers
Symbols SYNM ; DMN; SYN
External IDs OMIM: 606087 HomoloGene: 9081 GeneCards: SYNM Gene
Orthologs
Species Human Mouse
Entrez 23336 233335
Ensembl ENSG00000182253 ENSMUSG00000030554
UniProt O15061 Q70IV5
RefSeq (mRNA) NM_015286 NM_183312
RefSeq (protein) NP_056101 NP_899135
Location (UCSC) Chr 15:
99.1 – 99.14 Mb		 Chr 7:
67.73 – 67.76 Mb
PubMed search

Synemin also knowns as desmuslin is a protein that in humans is encoded by the SYNM gene.[1] Synemin is an intermediate filament (IF) family member. IF proteins are cytoskeletal proteins that confer resistance to mechanical stress and are encoded by a dispersed multigene family. This protein has been found to form a linkage between desmin, which is a subunit of the IF network, and the extracellular matrix, and provides an important structural support in muscle.

Function

Synemin is an intermediate filament (IF) and, like other IFs, primarily functions to integrate mechanical stress and maintain structural integrity in eukaryotic cells. While it has been observed in a variety of cell types, it has been best studied in the sarcomere of skeletal myocytes. It localizes at the Z-disk and has been shown to bind to α-dystrobrevin, α-actinin, and desmin to act as a mechanical linker in transmitting force laterally throughout the tissue, especially between the contractile myofibrils and extracellular matrix.

Properties

Synemin has properties very similar to the intermediate filament syncoilin. In particular, it binds to α-dystrobrevin in the dystrophin-associated protein complex to act as a mechanical "linker" between the myofibrillar network and the cell membrane.[2]

Splice variants

Two splice variant isoforms of synemin exist, α and β. Both isoforms have a very short N-terminal domain of 10 amino acids and a long C-terminal domain consisting of 1243 amino acids for the α isoform and 931 amino acids for the β isoform.[3] An intronic sequence of the synemin β isoform is used as a coding sequence for synemin α.[3]

History

The origin of the synemin/desmuslin naming convention is quite complex. In 1980, synemin was first identified in avian smooth muscle and was initially described as an IF-associated protein due to its colocalization and copurification with desmin and vimentin.[4] Subsequent to the cloning of chicken synemin, Mizuno and colleagues reported the cloning of a novel IF protein, human desmuslin, as an α-dystrobrevin-interacting protein.[2] Sequence analysis showed that human desmuslin was 32% identical and 11% similar to the amino acid sequence of chicken synemin, while the IF proteins vimentin and desmin are more than 80% identical across the same species. Although several parts were very similar between human desmuslin and chicken synemin, the low degree of conservation between these two proteins compared to other cloned IF proteins suggested that synemin was not the human desmuslin orthologue.[2] In addition, unlike chicken synemin, in vitro coimmunoprecipitation assays could not detect an interaction between human desmuslin and α-actinin.[2] In 2001, Titeux and colleagues reported the cloning of the α and β splice-varying isoforms of human synemin and showed that β-synemin was identical to desmuslin.[3]

References

  1. ↑ "Entrez Gene: Synemin, intermediate filament protein".
  2. 1 2 3 4 Mizuno Y, Thompson TG, Guyon JR, Lidov HG, Brosius M, Imamura M, Ozawa E, Watkins SC, Kunkel LM (May 2001). "Desmuslin, an intermediate filament protein that interacts with alpha -dystrobrevin and desmin". Proceedings of the National Academy of Sciences of the United States of America 98 (11): 6156–61. doi:10.1073/pnas.111153298. PMC 33438. PMID 11353857.
  3. 1 2 3 Titeux M, Brocheriou V, Xue Z, Gao J, Pellissier JF, Guicheney P, Paulin D, Li Z (Dec 2001). "Human synemin gene generates splice variants encoding two distinct intermediate filament proteins". European Journal of Biochemistry / FEBS 268 (24): 6435–49. doi:10.1046/j.0014-2956.2001.02594.x. PMID 11737198.
  4. ↑ Granger BL, Lazarides E (Dec 1980). "Synemin: a new high molecular weight protein associated with desmin and vimentin filaments in muscle". Cell 22 (3): 727–38. doi:10.1016/0092-8674(80)90549-8. PMID 7006832.

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

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