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Journal article

Carbohydrate- and conformation-dependent cargo capture for ER-exit.

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  • 2005-01-07
Published in:
  • Molecular biology of the cell. - 2005
Amino Acid Motifs
Amino Acid Sequence
Animals
Biological Transport
CHO Cells
Carbohydrates
Carrier Proteins
Cathepsin C
Cathepsin K
Cathepsins
Cricetinae
Cross-Linking Reagents
DNA
DNA, Complementary
Electrophoresis, Polyacrylamide Gel
Endoplasmic Reticulum
Glycoproteins
Glycoside Hydrolases
Humans
Immunoprecipitation
Lectins
Mannose-Binding Lectins
Membrane Proteins
Mice
Models, Molecular
Molecular Conformation
Molecular Sequence Data
Mutation
Oligosaccharides
Polysaccharides
Protein Conformation
Protein Folding
Protein Sorting Signals
Protein Structure, Secondary
Sequence Homology, Amino Acid
Transfection
English Some secretory proteins leave the endoplasmic reticulum (ER) by a receptor-mediated cargo capture mechanism, but the signals required for the cargo-receptor interaction are largely unknown. Here, we describe a novel targeting motif that is composed of a high-mannose type oligosaccharide intimately associated with a surface-exposed peptide beta-hairpin loop. The motif accounts for lectin ERGIC-53-assisted ER-export of the lyososomal enzyme procathepsin Z. The second oligosaccharide chain of procathepsin Z exhibits no binding activity for ERGIC-53, illustrating the selective lectin properties of ERGIC-53. Our data suggest that the conformation-based motif is only present in fully folded procathepsin Z and that its recognition by ERGIC-53 reflects a quality control mechanism that acts complementary to the primary folding machinery in the ER. A similar oligosaccharide/beta-hairpin loop structure is present in cathepsin C, another cargo of ERGIC-53, suggesting the general nature of this ER-exit signal. To our knowledge this is the first documentation of an ER-exit signal in soluble cargo in conjunction with its decoding by a transport receptor.
Language
  • English
Open access status
green
Identifiers
Persistent URL
https://sonar.ch/global/documents/2832
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