Pathways & interactions
FAS1 domain (IPR000782)
Short name: FAS1_domain
The FAS1 (fasciclin-like) domain is an extracellular module of about 140 amino acid residues. It has been suggested that the FAS1 domain represents an ancient cell adhesion domain common to plants and animals [PMID: 7925267]; related FAS1 domains are also found in bacteria [PMID: 7822037].
The crystal structure of FAS1 domains 3 and 4 of fasciclin I from Drosophila melanogaster (Fruit fly) has been determined, revealing a novel domain fold consisting of a seven-stranded beta wedge and at least five alpha helices; two well-ordered N-acetylglucosamine groups attached to a conserved asparagine are located in the interface region between the two FAS1 domains [PMID: 12575939]. Fasciclin I is an insect neural cell adhesion molecule involved in axonal guidance that is attached to the membrane by a GPI-anchored protein.
FAS1 domains are present in many secreted and membrane-anchored proteins. These proteins are usually GPI anchored and consist of: (i) a single FAS1 domain, (ii) a tandem array of FAS1 domains, or (iii) FAS1 domain(s) interspersed with other domains.
Proteins known to contain a FAS1 domain include:
- Fasciclin I (4 FAS1 domains).
- Human TGF-beta induced Ig-H3 (BIgH3) protein (4 FAS1 domains), where the FAS1 domains mediate cell adhesion through an interaction with alpha3/beta1 integrin; mutation in the FAS1 domains result in corneal dystrophy [PMID: 10906123].
- Volvox major cell adhesion protein (2 FAS1 domains) [PMID: 7925267].
- Arabidopsis fasciclin-like arabinogalactan proteins (2 FAS1 domains) [PMID: 16944204].
- Mammalian stabilin protein, a family of fasciclin-like hyaluronan receptor homologues (7 FAS1 domains)[PMID: 15345724].
- Human extracellular matrix protein periostin (4 FAS1 domains).
- Bacterial immunogenic protein MPT70 (1 FAS1 domain) [PMID: 7871388].
The FAS1 domains of both human periostin (Q15063) and BIgH3 (Q15582) proteins were found to contain vitamin K-dependent gamma-carboxyglutamate residues [PMID: 18450759]. Gamma-carboxyglutamate residues are more commonly associated with GLA domains (IPR000294), where they occur through post-translational modification catalysed by the vitamin K-dependent enzyme gamma-glutamylcarboxylase.