Testican-1: A Differentially Expressed Proteoglycan with Protease Inhibiting Activities

• Published in: International Review of Cytology Vol. 236; pp. 101 - 122
• Main Authors: Edgell, Cora-Jean S, BaSalamah, Mohammad A, Marr, Henry S
• Format: Book Chapter Journal Article
• Language: English
• Published: United States Elsevier Science & Technology 2004
• Subjects: Amino Acid Sequence; Animals; Astrocytes - cytology; Astrocytes - metabolism; Cathepsin L; Cathepsin L inhibitor; Cathepsins - antagonists & inhibitors; Cell Adhesion; Cell attachment inhibitor; Cellular biology; Cerebral Cortex - cytology; Cerebral Cortex - metabolism; Cysteine Endopeptidases; Glycosaminoglycans - metabolism; Humans; Matrix Metalloproteinases, Membrane-Associated; Metalloendopeptidases - antagonists & inhibitors; Molecular biology; MT-MMP inhibitor; Oligosaccharides - metabolism; Protease Inhibitors - metabolism; Protein Structure, Tertiary; Proteoglycan; Proteoglycans - genetics; Proteoglycans - metabolism; RNA, Messenger - metabolism; SPOCK; Testican; Tissue Distribution; Proteoglycan; Testican; Cathepsin L inhibitor; MT-MMP inhibitor; SPOCK; Cell attachment inhibitor
• ISBN: 9780123646408; 0123646405
• ISSN: 0074-7696; 2163-5854
• DOI: 10.1016/S0074-7696(04)36003-1

Testican-1 is a highly conserved, multidomain proteoglycan that is most prominently expressed in the thalamus of the brain, and is upregulated in activated astroglial cells of the cerebrum. Several functions of this gene product have now been demonstrated in vitro including membrane-type matrix metalloproteinase inhibition, cathepsin L inhibition, and low-affinity calcium binding. The purified gene product has been shown to inhibit cell attachment and neurite extensions in culture. Functions of testican in vivo have yet to be demonstrated in knockout mice or other models. Testican has been shown to carry substantial amounts of chondroitin sulfate as well as other oligosaccharides, but the biological significance of these embellishments is not yet known.