SUMMARY PARAGRAPH for PNG1
PNG1 encodes a soluble peptide:N-glycanase (PNGase), which catalyzes the deglycosylation of N-glycosylated proteins (1, 4). Misfolded secretory proteins and ER membrane proteins are exported from the ER to the cytosol, where they are deglycosylated by PNGase and then degraded by the proteasome, a process known as the ER quality control system (reviewed in references 5, 6, 7, and 8). Defects in ER quality control are associated with several human diseases, including cystic fibrosis, neurodegenerative diseases, and some viral infections (5).
Cells lacking Png1p are viable, and have no apparent growth defect, but have no detectable PNGase activity (1). In png1 null mutant cells, an abnormal form of carboxypeptidase Y (Prc1p) is degraded more slowly than in wild type cells (1). Png1p is found in both the cytosol and the nucleus (1). PNGase activity increases during stationary phase (4).
Proteins similar to Png1p are found in many eukaryotes, including S. pombe, C. elegans, D. melanogaster, mouse, and human (1).
Last updated: 2000-06-08