Fascin

fascin homolog 1
Crystallographic structure of dimeric human fascin 1.
Identifiers
Symbol	FSCN1
Alt. symbols	SNL
Entrez	6624
HUGO	11148
OMIM	602689
RefSeq	NM_003088
UniProt	Q16658
Other data
Locus	Chr. 7 p22

fascin homolog, retinal
Identifiers
Symbol	FSCN2
Entrez	25794
HUGO	3960
OMIM	607643
RefSeq	NM_012418
UniProt	O14926
Other data
Locus	Chr. 17 q25

fascin homolog 3, testicular
Identifiers
Symbol	FSCN3
Entrez	29999
HUGO	3961
RefSeq	NM_020369
UniProt	Q9NQT6
Other data
Locus	Chr. 7 q31.3

Fascin is an actin cross-linking protein.

Species and tissue distribution

It is a 54-58 kilodalton monomeric actin filament bundling protein originally isolated from sea urchin egg but also found in Drosophila and vertebrates, including humans. Fascin (from the Latin for bundle) is spaced at 11 nanometre intervals along the filament. The bundles in cross section are seen to be hexagonally packed, and the longitudinal spacing is compatible with a model where fascin cross-links at alternating 4 and 5 actins. It is calcium insensitive and monomeric. Three forms of fascin are found in vertebrates: Fascin1, widely found in the nervous system and elsewhere; fascin2 found in the retinal photoreceptor cells; fascin3, which is only found in the testes.

Function

Fascin binds beta-catenin, and colocalizes with it at the leading edges and borders of epithelial and endothelial cells. The role of Fascin in regulating cytoskeletal structures for the maintenance of cell adhesion, coordinating motility and invasion through interactions with signalling pathways is an active area of research especially from the cancer biology perspective. Fascin localizes to actin-rich protrusions at the cell surface called filopodia. Recent study shows that fascin also localizes to invadopodia, membrane protrusions formed at the adherent cell surface that facilitate extracellular matrix (ECM) invasion, this provide a potential molecular mechanism for how fascin increases the invasiveness of cancer cells since fascin expression is upregulated in a spectrum of cancers.

Clinical significance

Abnormal fascin expression or function has been implicated in breast cancer, colon cancer, esophageal squamous cell carcinoma, gallbladder cancer, pancreatic cancer, and prostate cancer. It is also helpful in identifying Hodgkin cells.

Structure

Fascin is a structural protein found in mesenchyme, nervous, and retinal tissue and is used in the bundling of actin molecules.

The structure of human fascin has been determined to a resolution of 1.8 Å (PDBID 3LLP) and reveals an arrangement of four tandem beta-trefoil domains that form a two lobed structure with pseudo 2-fold symmetry. It is stabilized by a hydrophobic core and a hydrophilic surface since it is often found inside cell cytoplasm in the formation of filopodia.

External links

• fascin at the US National Library of Medicine Medical Subject Headings (MeSH)

• PDB: 1DFC​;