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Glycosylation defects corrected by the changes in GDPmannose level.
J Kruszewska1, A Janik, U Lenart
1Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa.
Acta Biochimica Polonica
|November 5, 1999
Summary
Guanosine diphosphate mannose (GDPMan) is crucial for glycoprotein formation in yeast and fungi. Its availability impacts both early (ER) and later (Golgi) stages of glycoprotein synthesis, and deficiency causes neurological disorders.
Area of Science:
- Biochemistry
- Molecular Biology
- Glycobiology
Background:
- Guanosine diphosphate mannose (GDPMan) is essential for glycoprotein synthesis.
- In lower eukaryotes, GDPMan is involved in N-glycan and GPI-anchor formation, and O-mannosylation.
- GDPMan levels are known to influence Golgi-specific glycoprotein processing.
Purpose of the Study:
- To investigate the impact of GDPMan availability on early glycoprotein formation steps in the endoplasmic reticulum (ER).
- To explore the role of GDPMan in mannosyl-phosphodolichol (MPD) formation.
- To discuss the biochemical basis of GDPMan deficiency-related disorders.
Main Methods:
- Biochemical assays to assess GDPMan levels and their effects.
- Analysis of glycoprotein synthesis pathways in Saccharomyces cerevisiae.
- Review of existing evidence on GDPMan deficiency syndromes.
Main Results:
- GDPMan availability affects the elongation of outer mannose chains in the Golgi.
- GDPMan availability also impacts early ER-based glycoprotein formation, including dolichol-linked oligosaccharide assembly.
- GDPMan availability influences mannosyl-phosphodolichol (MPD) formation.
Conclusions:
- GDPMan plays a critical role throughout the entire glycoprotein synthesis pathway, from ER to Golgi.
- Understanding GDPMan's function is vital for comprehending glycoprotein synthesis and related disorders.
- Deficiency in GDPMan has significant implications for cellular function and human health, as seen in carbohydrate-deficient glycoprotein syndrome.