I-cell disease is a particularly severe form of lysosomal storage disease. Multiple enzymes are lacking in the lysosome and the organelle becomes stuffed with nondegraded material and therefore generates a so-called inclusion body. I-cell disease is inherited; it is caused by a single gene defect in the N-acetylglucosamine phosphotransferase that is required for the formation of mannose 6-phosphate (M6P) residues on lysosomal enzymes in the cis-Golgi. This enzyme recognizes soluble lysosomal enzymes as a class and hence a defect in this protein affects the targeting of a large number of proteins. What other defect(s) would cause the same phenotype? (Select all correct answers may be more than one)
A) a defect in clathrin function
B) a defect in the mannose 6-phosphate receptor
C) a defect in the phosphodiesterase that removes the GlcNAc group that initially covers the phosphate group on mannose 6-phosphate.
D) a defect in KDEL receptor
The other possible defect(s) that could cause the same phenotype are:
B) a defect in the mannose 6-phosphate receptor
C) a defect in the phosphodiesterase that removes the GlcNAc group that initially covers the phosphate group on mannose 6-phosphate.
I-cell disease is a particularly severe form of lysosomal storage disease. Multiple enzymes are lacking in...
CASE STUDY: Lysosomal Storage Disease Ensuring that proteins are targeted to the proper cellular destination is critical in eukaryotic cell function. Not only is this necessary for the protein to be in the proper place to carry out its function but also because certain post-translation modifications take place in the secretory pathway. Therefore improperly processed proteins may be defective in their biochemical activity even if they are located in the proper place in the cell. I-cell Disease (also called mucolipidosis)...
please answer all that you can 1. You have genetically engineered green fluorescent protein (GFP) containing a KDEL sequence (GFP-KDEL). When GFP-KDEL is expressed in normal human fibroblasts and examined using fluorescence microscopy, the fluorescence appears diffuse across the cytoplasm. How would you explain this observations given that KDEL is supposed to be an ER-specific sorting sequence? A. This engineered GFP would not have a hydrophobic signal sequence to get it into the RER in the first place. B. The...