Ectodomain shedding of neuroglycan C, a brain‐specific chondroitin sulfate proteoglycan, by TIMP‐2‐ and TIMP‐3‐sensitive proteolysis

• Published in: Journal of neurochemistry 2007-09, Vol.102 (5), p.1561-1568
• Main Authors: Shuo, Takuya, Aono, Sachiko, Nakanishi, Keiko, Tokita, Yoshihito, Kuroda, Yoshiyuki, Ida, Michiru, Matsui, Fumiko, Maruyama, Hiroyo, Kaji, Toshiyuki, Oohira, Atsuhiko
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Antibodies - pharmacology; Biochemistry; Brain; brain development; Cells, Cultured; Cellular biology; Cerebral Cortex - cytology; chondroitin sulfate proteoglycan; Dipeptides - pharmacology; Dose-Response Relationship, Drug; ectodomain shedding; Embryo, Mammalian; Gene Expression Regulation, Developmental - drug effects; Glycoproteins; Hydroxamic Acids - pharmacology; Immunoprecipitation - methods; Membrane Proteins - immunology; Membrane Proteins - metabolism; metalloproteinase; Molecular Weight; neuroglycan C; Neurology; Neurons - drug effects; Neurons - metabolism; Protease Inhibitors - pharmacology; Proteoglycans - immunology; Proteoglycans - metabolism; Rats; Rats, Sprague-Dawley; Rodents; Time Factors; tissue inhibitor of metalloproteinase; Tissue Inhibitor of Metalloproteinase-2 - antagonists & inhibitors; Tissue Inhibitor of Metalloproteinase-3 - antagonists & inhibitors
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2007.04658.x

Neuroglycan C (NGC) is a transmembrane‐type of chondroitin sulfate proteoglycan with an epidermal growth factor (EGF)‐like module that is exclusively expressed in the CNS. Because ectodomain shedding is a common processing step for many transmembrane proteins, we examined whether NGC was subjected to proteolytic cleavage. Western blotting demonstrated the occurrence of a soluble form of NGC with a 75 kDa core glycoprotein in the soluble fraction of the young rat cerebrum. In contrast, full‐length NGC with a 120 kDa core glycoprotein and its cytoplasmic fragment with a molecular size of 35 kDa could be detected in the membrane fraction. The soluble form of NGC was also detectable in culture media of fetal rat neurons, and the full‐length form existed in cell layers. The amount of the soluble form in culture media was decreased by adding a physiological protease inhibitor such as a tissue inhibitor of metalloproteinase (TIMP)‐2 or TIMP‐3, but not by adding TIMP‐1. Both EGF‐like and neurite outgrowth‐promoting activity of the NGC ectodomain may be regulated by this proteolytic processing.