The pro-peptide of the pro beta-polypeptide chain of human beta-hexosaminidase is necessary for proper protein folding and exit from the endoplasmic reticulum.
We examine the function of the pro beta-peptide (residues 42-121) in the folding and intracellular transport of human beta-hexosaminidase B (beta-N-acetylhexosaminidase, EC 3.2.1.52). A construct was prepared that encoded an in frame deletion of residues 55-118. Expression of this construct in COS-1 cells produced a beta-polypeptide chain that formed insoluble aggregates and remained trapped in the endoplasmic reticulum (ER). We conclude that the pro beta-peptide may act as a type of intramolecular chaperone for the mature beta-subunit.
Sagherian
C
C
Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.
Thorner
P
P
Mahuran
D
D
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002522:Chlorocebus aethiops; D002884:Chromosomes, Human, Pair 15; D002895:Chromosomes, Human, Pair 5; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007668:Kidney; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D001619:beta-N-Acetylhexosaminidases / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*
D046911:Macromolecular Substances; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D001619:beta-N-Acetylhexosaminidases