Testican 3 (TIC3)

The cDNA was a splice variant of SPOCK3, which the authors called testican-3, and included the N-terminal 313-amino acid region of SPOCK3 with a 3-amino acid substitution at the C terminus; the authors designated the splice variant N-TES. N-TES contains a signal peptide, a unique domain, a follistatin-like domain, and a Ca(2+)-binding domain, but lacks a C-terminal thyroglobulin domain and 2 putative glycosaminoglycan attachment sites of SPOCK3. The full-length SPOCK3 protein contains 436 amino acids and shares 51% and 44% homology with SPOCK1 and SPOCK2 , respectively. Semiquantitative RT-PCR detected expression of SPOCK3 and N-TES transcripts in normal brain; transcripts of both were downregulated in glioma tissues.