Title : Characterization of the expression, promoter activity and molecular architecture of
fibin
Abstract :
- BACKGROUND: Fibin was initially discovered as a secreted signal molecule essential for pectoral fin bud initiation in zebrafish
- Currently, there is little information about the molecular architecture and biological relevance of fibin in humans and other mammals
- RESULTS: Fibin is expressed in cerebellum, skeletal muscle and many other embryonic and adult mouse tissues suggesting not only a role during embryonic development but also in adult functions
- A 2.5- kbp genomic sequence fragment upstream of the coding sequence is sufficient to drive and regulate fibin expression through stimulation by glucocorticoids, activators of the protein kinase C signalling pathways and manganese ions
- Fibin is an evolutionarily conserved protein , carries a cleavable signal peptide (amino acids 1-18) and is glycosylated at Asn30
- The two conserved cysteines participate in intermolecular disulfide bond and multimer formation
- Although fibin displays all features of a secretory protein, it is mostly retained in the endoplasmic reticulum when heterologously expressed
- CONCLUSION: Fibin is functionally relevant during embryogenesis and adult life
- Its expression is regulated by a number of cellular signalling pathways and the protein is routed via the secretory pathway
- However, proper secretion presumably requires an unknown covalently-linked or associated co-factor