Alternative titles; symbols
HGNC Approved Gene Symbol: SPOCK2
Cytogenetic location: 10q22.1 Genomic coordinates (GRCh38) : 10:72,059,034-72,089,032 (from NCBI)
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 (summary by Vannahme et al., 1999).
By screening an immature myeloid cell line for cDNAs with the potential to encode large proteins, Nagase et al. (1996) identified a SPOCK2 cDNA, which they called KIAA0275, encoding a protein with sequence similarity to testican (SPOCK1; 602264) and with a thyroglobulin type-1 repeat. Northern blot analysis detected highest expression in brain, thymus, and peripheral blood leukocytes.
By screening a human brain cDNA library with a fragment of an EST showing sequence similarity to the follistatin-like domain of a BM-40/SPARC/osteonectin (182120), Vannahme et al. (1999) cloned a SPOCK2 cDNA, which they called testican-2, encoding a deduced precursor protein of 424 amino acids with a 22-amino acid signal peptide and a calculated molecular mass of 46.8 kD. 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. In situ hybridization demonstrated widespread expression in multiple neuronal cell types in olfactory bulb, cerebral cortex, hippocampus, thalamus, cerebellum, pons, and medulla. A recombinant fragment consisting of the Ca(2+)-binding EF-hand domain and the thyroglobulin-like domain showed a reversible Ca(2+)-dependent conformational change in circular dichroism studies.
By radiation hybrid analysis, Nagase et al. (1996) mapped the SPOCK2 gene to chromosome 10. By sequence analysis, Vannahme et al. (1999) localized the gene to 10q21-q23.
Nagase, T., Seki, N., Ishikawa, K., Ohira, M., Kawarabayasi, Y., Ohara, O., Tanaka, A., Kotani, H., Miyajima, N., Nomura, N. Prediction of the coding sequences of unidentified human genes. VI. The coding sequences of 80 new genes (KIAA0201-KIAA0280) deduced by analysis of cDNA clones from cell line KG-1 and brain. DNA Res. 3: 321-329, 1996. Note: Supplement: DNA Res. 3: 341-354, 1996. [PubMed: 9039502] [Full Text: https://doi.org/10.1093/dnares/3.5.321]
Vannahme, C., Schubel, S., Herud, M., Gosling, S., Hulsmann, H., Paulsson, M., Hartmann, U., Maurer, P. Molecular cloning of testican-2: defining a novel calcium-binding proteoglycan family expressed in brain. J. Neurochem. 73: 12-20, 1999. [PubMed: 10386950] [Full Text: https://doi.org/10.1046/j.1471-4159.1999.0730012.x]