High impact information on SEC59

• In mutants affecting translocation into (sec59) and passage from (sec 18) the endoplasmic reticulum, a glycosylated form of the precursor containing three N-linked core oligosaccharides accumulates; however, it appears that the signal peptide is not removed [1].
• A portion of the invertase polypeptide accumulated at 37 degrees C is preserved when membranes from sec53 and sec59 are treated with trypsin [2].
• DK1 is responsible for the final step of the de novo biosynthesis of dolichol phosphate [3].
• The mutated alleles failed to complement the temperature-sensitive phenotype of DK1-deficient yeast cells, whereas the wild-type allele restored the normal growth phenotype [3].
• Among the mutants identified by this screen were sec59 (which encodes dolichol kinase) and a mutant that affects the activity of the ALG1-encoded mannosyltransferase that forms dolichol-PP-(GlcNAc)2Man1 [4].

Biological context of SEC59

• Molecular cloning and DNA sequence analysis of the SEC59 gene predicted an extremely hydrophobic protein product of 59 kilodaltons [5].
• The CTP-mediated phosphorylation of diacylglycerol (DAG) is unaffected by either the temperature-sensitive mutation in the sec59-1 strain, overexpression of the SEC59 gene, or the mammalian homolog hDK1 under conditions that produced a loss or elevation in the level of DK activity [6].
• Genetic mapping experiments revealed that ERG6 is located on chromosome XIII, tightly linked to sec59 [7].
• When sec59 cells were transformed with a plasmid that overexpresses the wild-type gene, dolichol kinase activity increased 10-fold over wild-type levels [8].
• Sec59 encodes a membrane protein required for core glycosylation in Saccharomyces cerevisiae [5].

Anatomical context of SEC59

• Dolichol kinase (DK) catalyzes the CTP-mediated phosphorylation of dolichol in eukaryotic cells, the terminal step in dolichyl monophosphate (Dol-P) biosynthesis de novo [6].

Associations of SEC59 with chemical compounds

• Yeast secretory mutants sec53 and sec59 define a posttranslational stage in the penetration of glycoprotein precursors into the endoplasmic reticulum (ER) [2].
• Quantitative measurements of dolichyl phosphate in sec59 cells showed that the levels were decreased to 48% of wild type at the permissive temperature and to less than 10% at the restrictive temperature [8].
• These results were consistent with a role for the Sec59 protein in the transfer of mannose to dolichol-linked oligosaccharide [5].

Other interactions of SEC59

• The secretion mutant sec59 has a similar phenotype to dpm1, and the presence of a dolichol recognition sequence in the SEC59 protein gave a clue to its defect, which is in dolichol kinase [9].

References