Tsukushin (TSK)

Tsk is a BMP inhibitor in oviparous vertebrates that forms a ternary complex with Bmp and chordin and is involved in the regulation of primitive streak and Hensen node.Using transcript-specific PCR primers for novel sequences that increased more than 10-fold upon treatment with 17-beta estradiol (E2), they cloned 5 cDNAs, designated E2-induced genes (E2IG) 1-5, from a human placenta cDNA library. The E2IG4 cDNA encodes a deduced 353-amino acid protein containing a leucine-rich repeat in the N terminus and 8 additional leucine-rich repeats. E2IG4 demonstrates domain and structural homology to extracellular matrix leucine-rich proteoglycans such as decorin and biglycan . It also contains various potential phosphorylation sites.