Biosynthesis of intestinal microvillar proteins. Further characterization of the intracellular processing and transport
Research output: Contribution to journal › Journal article › Research › peer-review
The effect of tunicamycin on synthesis and intracellular transport of pig small intestinal aminopeptidase N (EC 3.4.11.2), sucrase-isomaltase (EC 3.2.1.48-10) and maltase-glucoamylase (EC 3.2.1.20) was studied by labelling of mucosal explants with [35S]methionine. The expression of the microvillar enzymes was greatly reduced by tunicamycin but could be partially restored by leupeptin, suggesting the existence of a mechanism whereby newly synthesized, malprocessed enzymes are recognized and degraded. In the presence of tunicamycin, polypeptides likely to represent non-glycosylated forms of the enzymes persisted in the Mg2+-precipitated membrane fraction, indicating that high mannose glycosylation is essential for transport to the microvillar membrane. Treatment of aminopeptidase N and sucrase-isomaltase with endo F reduced the size of the high mannose forms approximately to those seen in the presence of tunicamycin. The complex forms were also sensitive to endo F but did not coincide with the high mannose forms after treatment, indicating that the size difference cannot alone be ascribed to processing of N-linked carbohydrate.
Original language | English |
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Journal | FEBS Letters |
Volume | 166 |
Issue number | 1 |
Pages (from-to) | 28-32 |
Number of pages | 4 |
ISSN | 0014-5793 |
Publication status | Published - 1984 |
Bibliographical note
Keywords: Aminopeptidases; Animals; Biological Transport; Glucosamine; Glucosidases; Glycoproteins; Intestinal Mucosa; Leupeptins; Microvilli; Molecular Weight; Multienzyme Complexes; Sucrase-Isomaltase Complex; Swine; Tunicamycin; alpha-Glucosidases
ID: 9881401