Glycosylation site for chondroitin sulfate on the neural part-time proteoglycan, neuroglycan C.
Neuroglycan C (NGC) is a membrane-spanning chondroitin sulfate (CS) proteoglycan that is expressed predominantly in the central nervous system (CNS). NGC dramatically changed its structure from a proteoglycan to a nonproteoglycan form with cerebellar development, whereas a small portion of NGC molecules existed in a nonproteoglycan form in the other areas of the mature CNS, suggesting that the CS glycosylation of NGC is developmentally regulated in the whole CNS. As primary cultured neurons and astrocytes from cerebral cortices expressed NGC in a proteoglycan form and in a nonproteoglycan form, respectively, CS glycosylation seems to be regulated differently depending on cell type. To investigate the glycosylation process, cell lines expressing a proteoglycan form of NGC would be favorable experimental models. When a mouse NGC cDNA was transfected into COS 1, PC12D, and Neuro 2a cells, only Neuro 2a cells, a mouse neuroblastoma cell line, expressed NGC bearing CS chains. In PC12D cells, although three intrinsic CS proteoglycans were detected, exogenously expressed NGC did not bear any short CS chains just like NGC in the mature cerebellum. This suggests that the addition of CS chains to the NGC core protein is regulated in a manner different from that of other CS proteoglycans. As the first step in investigating the CS glycosylation mechanism using Neuro 2a cells, we determined the CS attachment site as Ser-123 on the NGC core protein by site-directed mutagenesis. The CS glycosylation was not necessary for intracellular trafficking of NGC to the cell surface at least in Neuro 2a cells.
Department of Perinatology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi 480-0392, Japan. saono@inst-hsc.jp
Sachiko
S
Aono
Yoshihito
Y
Tokita
Takuya
T
Shuo
Shinobu
S
Yamauchi
Fumiko
F
Matsui
Keiko
K
Nakanishi
Kanako
K
Hirano
Mamoru
M
Sano
Atsuhiko
A
Oohira
D000367:Age Factors; D000595:Amino Acid Sequence; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001665:Binding Sites; D019921:Biotinylation; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D002490:Central Nervous System; D002531:Cerebellum / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000737:chemistry*; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D008565:Membrane Proteins / Q000737:chemistry*; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009474:Neurons / Q000378:metabolism; D016716:PC12 Cells; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011509:Proteoglycans / Q000737:chemistry*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013687:Telencephalon / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
C403173:Cspg5 protein, mouse; D018076:DNA, Complementary; D008565:Membrane Proteins; D011509:Proteoglycans; D002809:Chondroitin Sulfates