| Primary Identifier | IPR019577 | Type | Domain |
| Short Name | SPARC/Testican_Ca-bd-dom |
| description | 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 [, ]. Testican-3 appears to be a novel regulator that reduces the activity of matrix metalloproteinase (MMP) in adult T-cell leukemia (ATL) [].This cysteine-rich domain is responsible for the anti-spreading activity of human urothelial cells. This extracellular calcium-binding domain is rich in α-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 []. |
