Related Experiment Videos
The complex-type glycoprotein secreted by the bovine subcommissural organ: an immunological study using C1B8A8
R Meiniel1, N Duchier-Liris, J L Molat
1Laboratoire de Biochimie Médicale, Université d'Auvergne, Faculté de Médecine, Clermont-Ferrand, France.
Insights
Researchers investigated the complex-type glycoprotein secretion in the subcommissural organ (SCO) using a specific antibody. They identified precursor, intermediate, and monomeric forms of the glycoprotein, suggesting dual secretion into cerebrospinal fluid and perivascular spaces.
Area of Science:
- Neuroscience
- Glycobiology
- Cell Biology
Background:
- The subcommissural organ (SCO) secretes a complex-type glycoprotein into the cerebrospinal fluid.
- The exact secretory pathway and forms of this glycoprotein are not fully understood.
Purpose of the Study:
- To elucidate the secretory pathway of the SCO-specific complex-type glycoprotein.
- To identify different glycopeptide forms involved in the secretion process.
Main Methods:
- Utilized a specific monoclonal antibody (Mab C1B8A8) for immunodetection.
- Employed immunoaffinity chromatography and Western blotting to analyze glycopeptides.
- Conducted comparative analysis with ependymal cell extracts.
Main Results:
- Immunoreactive material detected in endoplasmic reticulum, Golgi, secretory vacuoles, and ventricular cavity of SCO ependymocytes.
- Evidence suggests secretion into both cerebrospinal fluid and perivascular spaces.
- Identified three Concanavalin A (Con A)-positive glycopeptides (88, 54, 34 kDa) and two Wheat Germ Agglutinin (WGA)-positive glycopeptides (54, 34 kDa).
- The 88 kDa glycopeptide is likely a high-mannose precursor, the 54 kDa an intermediate form, and the 34 kDa a monomeric form.
Conclusions:
- The study maps the secretory pathway of the SCO glycoprotein within ependymocytes.
- Identified distinct glycopeptide forms representing different stages of glycoprotein processing and secretion.
- The findings suggest a dual secretion mechanism for the SCO glycoprotein into both CSF and perivascular spaces.
Abstract:
The secretory pathway of the complex-type glycoprotein specific to the subcommissural organ (SCO) was examined using the monoclonal antibody (Mab) C1B8A8. Immunoreactive material was revealed in various compartments of the secretory ependymocyte, i.e., the endoplasmic reticulum, the Golgi area and the secretory vacuoles. In addition, immunoreactive material was also observed in the ventricular cavity. Evidence of a release both at the apical lining and at the basal process of the SCO ependymocytes suggests that the same protein could be secreted into the cerebrospinal fluid and the perivascular spaces. After immunoaffinity chromatography of soluble extracts of the SCO on Mab C1B8A8 immunoadsorbent columns, three glycopeptides were identified on Western blots; they were concanavalin A (Con A)-positive (88, 54 and 34 kDa) and wheat-germ agglutinin (WGA)-positive (54 and 34 kDa). The Con A-positive glycopeptide (88 kDa) is probably related to the high-mannose-type glycoprotein, the precursor form of the secreted compound, whereas the 54 kDa-glycopeptide that is both Con A- and WGA-positive could represent an intermediate form. The 34 kDa-glycopeptide that is strongly WGA-positive could be related to the monomeric form of the secreted compound. These three glycopeptides were not revealed in eluted fractions of soluble extracts of the ependyma that served as control.