Testican-1 is also known as protein SPOCK/SPOCK1, which contains one azal-like domain and one thyroglobulin type-1 domain.SPOCK1 is an extracellular heparan/chondroitin sulfate proteoglycan. Members of this family are known as testicans, also called SPOCKs. SPOCKs are enriched in brain and have been shown to regulate neuronal attachment and outgrowth. They contain inhibitory regions in several domains targeted to different classes of protease, and in some cases may act as protease inhibitors. Little is known about SPOCK1's function until now. It may play a role in cell-cell and cell-matrix interactions except for contributing to various neuronal mechanisms in the central nervous system.