title: Testican-3: a brain-specific proteoglycan member of the BM-40/SPARC/osteonectin family.
abstract: The testicans are a three-member family of secreted proteoglycans structurally related to the BM-40/secreted protein acidic and rich in cystein (SPARC) osteonectin family of extracellular calcium-binding proteins. In vitro studies have indicated that testicans are involved in the regulation of extracellular protease cascades and in neuronal function. Here, we describe the biochemical characterization and tissue distribution of mouse testican-3 as well as the inactivation of the corresponding gene. The expression of testican-3 in adult mice is restricted to the brain, where it is located diffusely within the extracellular matrix, as well as associated with cells. Brain-derived testican-3 is a heparan sulphate proteoglycan. In cell culture, the core protein is detected in the supernatant and the extracellular matrix, whereas the proteoglycan form is restricted to the supernatant. This indicates possible interactions of the testican-3 core protein with components of the extracellular matrix which are blocked by addition of the glycosaminoglycan chains. Mice deficient in testican-3 are viable and fertile and do not show an obvious phenotype. This points to a functional redundancy among the different members of the testican family or between testican-3 and other brain heparan sulphate proteoglycans.
authors: Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany. ursula.hartmann@uni-koeln.de
authors: Ursula
authors: U
authors: Hartmann
authors: Hanni
authors: H
authors: Hülsmann
authors: Judith
authors: J
authors: Seul
authors: Sandra
authors: S
authors: Röll
authors: Heven
authors: H
authors: Midani
authors: Isabelle
authors: I
authors: Breloy
authors: Daniel
authors: D
authors: Hechler
authors: Regina
authors: R
authors: Müller
authors: Mats
authors: M
authors: Paulsson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D005109:Extracellular Matrix / Q000378:metabolism; D005354:Fibrosarcoma / Q000473:pathology; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015676:Osteonectin / Q000378:metabolism*; D011509:Proteoglycans / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
chemical_list: D015676:Osteonectin; D011509:Proteoglycans; C504370:Spock1 protein, mouse; C504410:Spock3 protein, mouse