A role for Follistatin-like protein 1 (FSTL1) in colorectal cancer

摘要

Follistatin-like protein 1 [FSTL1, alternative names: TGFβ-induced clone 36 (TSC36) or Follistatin-Related Protein (FRP)] is a glycosylated 308 amino-acid secreted protein expressed in various human tissues ( ). It plays various roles in vertebrate development including the dorso-ventral axis establishment and skeletal, lung and ureter development ( ). In mice, disruption of the gene results in neonatal mortality hours after birth with respiratory distress ( ). In human adult tissues FSTL1 mRNA is most abundantly expressed in adipose tissue, urinary bladder, prostate and endometrium ( ). FSTL1 belongs to the SPARC (Secreted Protein Acid and Rich in Cysteine) family of proteins together with SPARC, FSTL4, FSTL5, SMOC1, SMOC2, hevin and testican-1, -2 and -3. Similar to other members of the family, FSTL1 possesses a follistatin domain and an extracellular calcium-binding (EC) domain. In human FSTL1 these domains occupy a position from amino acids 31 to 98 and from 113 to 232 respectively ( ). More amino-terminal (amino acids 1–20), FSTL1 possesses a signal domain required for secretion of the protein. Carboxyterminal to EC domain, from amino acids 232 to 271 of the protein, a von Willebrand C type domain is present, which functions in protein-protein interactions.