engleski

Protein glycosylation – an evolutionary crossroad between genes and environment

The majority of molecular processes in higher organisms is performed by various proteins and is thus determined by genes that encode these proteins. However, a significant structural component of at least a half of all cellular proteins is not a polypeptide encoded by a single gene, but oligosaccharide (glycan) synthesized by a network of proteins resulting from the expression of hundreds of different genes. Relationships between hundreds of individual proteins that participate in glycan biosynthesiss are very complex what enables influence of environmental factors on the final structure of glycans, either by direct effects on individual enzymatic processes, or by induction of epigenetic changes that modify gene expression patterns. Until recently, the complexity of glycan structures prevented large scale studies of protein glycosylation, but recent advancements in both glycan analysis and genotyping technologies enabled first insights into the intricate field of complex genetics of proteins glycosylation. Mutations which inactivate genes involved in the synthesis of common N-glycan precursor are embryonically lethal. However, mutations in genes involved in modifications of glycan antennas are common and apparently contribute largely to individual phenotypic variations that exist in humans and other higher organisms. Some of these variations can be recognized as specific glyco-phenotypes that might represent specific evolutionary advantages or disadvantages, which are however amenable to environmental influences and a¬re thus less pre-determined than classical Mendelian mutations.

protein glycosylation; glycome; complex genetics of glycosylation; glyco-phenotypes; epigenetic regulation

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