SPARC/Testican, calcium-binding domain (IPR019577)

Short name: SPARC/Testican_Ca-bd-dom

Domain relationships



This entry represents the calcium-binding domain found in SPARC (Secreted Protein Acidic and Rich in Cysteine) and Testican (also known as SPOCK; or SParc/Osteonectin, Cwcv and Kazal-like domains) proteins. SPARC proteins are down-regulated in various tumours and may have a tumour-suppressor function [PMID: 18459035, PMID: 17325739]. Testican-3 appears to be a novel regulator that reduces the activity of matrix metalloproteinase (MMP) in adult T-cell leukemia (ATL) [PMID: 19144404].

This cysteine-rich domain is responsible for the anti-spreading activity of human urothelial cells. This extracellular calcium-binding domain is rich in alpha-helices and contains two EF-hands that each coordinates one Ca2+ ion, forming a helix-loop-helix structure that not only drives the conformation of the protein but is also necessary for biological activity. The anti-spreading activity was dependent on the coordination of Ca2+ by a Glu residue at the Z position of EF-hand 2 [PMID: 16121393].

GO terms

Biological Process

GO:0007165 signal transduction

Molecular Function

GO:0005509 calcium ion binding

Cellular Component

GO:0005578 proteinaceous extracellular matrix

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.