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pH-independent and -dependent cleavage of proinsulin in the same secretory vesicle.

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  • 1994-09-01
Published in:
  • The Journal of cell biology. - 1994
Ammonium Chloride
Animals
Cytoplasmic Granules
Glucose
Hydrogen-Ion Concentration
In Vitro Techniques
Islets of Langerhans
Proinsulin
Protein Processing, Post-Translational
Rats
Rats, Sprague-Dawley
English By quantitative immunoelectron microscopy and HPLC, we have studied the effect of disrupting pH gradients, by ammonium chloride, on proinsulin conversion in the insulin-producing B-cells of the islets of langerhans. Proinsulin content and pH in single secretory vesicles were measured on consecutive serial sections immunostained alternately with anti-proinsulin or anti-dinitrophenol (to reveal the pH-sensitive probe DAMP) antibodies. Radioactivity labeled proinsulin, proinsulin cleavage intermediates, and insulin were quantitated by HPLC analysis of extracts of islets treated in the same conditions. Cleavage at the C-peptide/A-chain junction is significantly less sensitive to pH gradient disruption than that of the B-chain/C-peptide junction, but the range of pH and proinsulin content in individual vesicles indicate that both cleavages occur in the same vesicle released from the TGN.
Language
  • English
Open access status
bronze
Identifiers
Persistent URL
https://sonar.ch/global/documents/252626
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