|Detection of Rat Testican 2/SPOCK2 by Western Blot. Western blot shows lysates of rat lung tissue. PVDF Membrane was probed with 1 µg/mL of Goat Anti-Human/Mouse/Rat Testican 2/SPOCK2 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF2328) followed by HRP-conjugated Anti-Goat IgG Secondary Antibody (Catalog # HAF019). A specific band was detected for Testican 2/SPOCK2 at approximately 140 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 8.|
Testican 2 (also SPOCK2) is a 60 - 140 kDa, secreted multidomain proteoglycan that belongs to the BM-40/SPARC family of extracellular proteins. It is expressed by neurons (both excitatory and GABAergic) plus brain endothelial cells, and appears to abrogate testican 1 and 3 mediated inhibition of MT1- and MT3-MMP activity. Mature human Testican 2 is 402 amino acids (aa) in length (aa 23 - 424). It contains a unique 66 aa N terminus, followed by a Kazal-like follistatin domain (aa 89-192), a collagen-binding domain (aa 210-219), a Ca++ binding region, one thyroglobulin-like segment (aa 310-376) and an acidic C-terminus that contains two potential GAG attachment sites at Ser383 and Ser388. The wide variation in native MW reflects the capabilities of differing cells to add glycan adducts to the molecule. Typically, it appears to lie belween 80-125 kDa. There are potential splice variants. One shows an alternative start site at Met110, a second shows a deletion of aa 64-66, while a third contains a 14 aa substitution for aa 64-242. Mature human Testican 2 is 94% aa identical to mouse and rat Testican 2.