Extracellular matrix protein fibronectin (FN) plays an important role in cell adhesion. FN contains FN type I, II and III domains. The FN III repeat is generally about 90 amino acids long and to be composed of seven b-strands, forming two antiparallel b-sheets. FN III domain derived proteins have been demonstrated to bind various proteins with high affinity. Human fibronectin type III domain-containing protein 4 (FNDC4) mRNA was highly enriched in human liver, brain tissue and adipocytes. Currently, FNDC4 function is unknown, but FNDC5 function was recently demonstrated to be a key player in regulation of brown fat cell differentiation.

Full-length extracellular domain of human FNDC4 cDNA (45 - 167aa, derived from BC032725) was constructed with codon optimization with a small T7-His-TEV cleavage site Tag (29aa) fusion at its N-terminal. This protein was expressed in E. coli as inclusion bodies, refolded using our unique “temperature shift inclusion body refolding” technology and chromatographically purified.

1. May be used for in vitro human FNDC4 functional study using recombinant FNDC4 protein mediated intracellular delivery.

2. May be used as specific substrate protein for kinase and ubiquitin related enzyme functional screening assays.

3. May be used as antigen for specific antibody production.