ALG1 (Asparagine-linked glycosylation protein 1) proteins participate in the formation of the lipid-linked precursor oligosaccharide for N-glycosylation. They are also involved in assembling the dolichol-pyrophosphate-GlcNAc(2)-Man5 intermediate on the cytoplasmic surface of the ER [, ].Defects in human ALG1 are the cause of congenital disorder of glycosylation type 1K (CDG1K). CDGs are characterised by under-glycosylated serum proteins. These multisystem disorders present with a wide variety of clinical features, such as disorders of the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. [, , ].Glycosylation and growth of Alg1-deficient PRY56 yeast cells, showing a temperature-sensitive phenotype, could be restored by the human wild-type allele [].
