SAG: a Schwann cell membrane glycoprotein

• Published in: The Journal of neuroscience 1992-06, Vol.12 (6), p.2177-2185
• Main Authors: Dieperink, ME, O'Neill, A, Magnoni, G, Wollmann, RL, Heinrikson, RL, Zucher-Neely, HA, Stefansson, K
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; biochemical characteristics; Biological and medical sciences; Blotting, Western; Carbohydrate Metabolism; Fundamental and applied biological sciences. Psychology; Humans; Isolated neuron and nerve. Neuroglia; Lectins; membrane glycoproteins; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; Molecular Sequence Data; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Peripheral Nerves - metabolism; Rats; Rats, Inbred Lew; Schwann cells; Schwann Cells - metabolism; Staining and Labeling; Tissue Distribution; Vertebrates: nervous system and sense organs
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/JNEUROSCI.12-06-02177.1992

We report on characterization of a 170,000 Da glycoprotein found exclusively in the PNS. We refer to this protein as the Schwann cell membrane glycoprotein (SAG). SAG contains the HNK-1 carbohydrate, which is considered by some to be a marker of adhesion molecules. Its N-terminal sequence is not similar to previously known polypeptide sequences. SAG is found exclusively in the PNS, is present in rat sciatic nerve prior to myelination, and is in both myelinating and nonmyelinating Schwann cells. Tumors of Schwann cell lineage express SAG where axons are present (neurofibromas) but do not in the absence of axons (schwannomas). Schwannoma cells in culture do not express SAG even when exposed to forskolin, an activator of adenylate cyclase. However, schwannoma cells grown in the presence of a neuronal cell line (PC12) express SAG.