Testican 2 (TIC2)

Proteoglycans, which consist of a core protein and covalently linked glycosaminoglycans, are components of the extracellular matrix. SPOCK2 encodes a member of a novel Ca(2+)-binding proteoglycan family.

The mature 402-amino acid protein has 5 domains: a follistatin-like domain, a Ca(2+)-binding domain, a thyroglobulin-like domain, and a C-terminal region with 2 putative glycosaminoglycan attachment sites. The SPOCK2 protein shares 43% overall sequence identity with SPOCK1. Northern blot analysis of adult mouse tissues revealed expression of a major 6.1-kb transcript at high levels in brain and at low levels in lung and testis. Minor bands of 4.4 and 2.6 kb were also detected.