, Volume 30, Issue 5, pp 348–353 | Cite as

Resistance of the insulin crystal to lysosomal proteases: implications for pancreatic B-cell crinophagy

  • P. A. Halban
  • R. Mutkoski
  • G. Dodson
  • L. Orci


Insulin is thought to be chemically stabilized within β-granules in the crystal form. The other major products of the β-granule, proinsulin and C-peptide, by contrast, are not thought able to crystallize. The physico-chemical properties of peptides in soluble or crystalline form are dramatically different. The ability of insulin to crystallize in the β-granule might thus explain why this peptide, but not proinsulin/Cpeptide, remains stable even after its introduction into lysosomes as occurs during granulolysis (crinophagy). We have now studied this by exposing proinsulin or insulin to lysosomal proteases in vitro. 125I-insulin in soluble form was found to be degraded at the same rate as 125I-proinsulin. Strikingly, however, when the labelled insulin was crystallized, its rate of degradation was decreased from 1.9 to 0.2 pmol/min. We take these data as confirmation that the insulin crystal is resistant to degradation, thereby possibly accounting for (a) the presence of insulin immunoreactivity within multigranular bodies, and (b) the unusually slow rate of degradation of insulin within B cells compared with that of other hormones in their cells of origin.

Key words

Insulin proinsulin crinophagy insulin crystals degradation lysosomes 


  1. 1.
    Bienkowski RS (1983) Intracellular degradation of newly synthesized secretory proteins. Biochem J 214: 1–10Google Scholar
  2. 2.
    Amherdt M, Orci L, Stauffacher W, Renold AE, Rouiller C (1970) Morphological evidence suggestive of an impairment of insulin secretion in vivo in normoglycemic spiny mice (Acomys cahirinus). In: Favard P (ed) International Congress for Electron Microscopy, Grenoble, France. Société Franfaise de Microscopic Electronique, Paris, p 501Google Scholar
  3. 3.
    Creutzfeldt W, Creutzfeldt C, Frerichs H, Perings E, Sickinger K (1969) The morphological substrate of the inhibition of insulin secretion by diazoxide. Horm Metab Res 1: 53–64Google Scholar
  4. 4.
    Halban PA, Wollheim CB (1980) Intracellular degradation of insulin stores by pancreatic islets in vitro: an alternative pathway for homeostasis of pancreatic insulin content. J Biol Chem 255: 6003–6006Google Scholar
  5. 5.
    Smith RE, Farquhar MG (1966) Lysosome function in the regulation of the secretory process in cells of the anterior pituitary gland. J Cell Biol 31: 319–346Google Scholar
  6. 6.
    Orci L, Ravazzola M, Amherdt M, Yanaihara C, Yanaihara C, Halban P, Renold AE, Perrelet A (1984) Insulin, not C-peptide (proinsulin), is present in crinophagic bodies of the pancreatic B cell. J Cell Biol 98: 222–228Google Scholar
  7. 7.
    Ragab H, Beck C, Dillard C, Tappel AL (1967) Preparation of rat liver lysosomes. Biochim Biophys Acta 148: 501–505Google Scholar
  8. 8.
    Armbruster BL, Carlemalm E, Chiovetti P, Garavito RM, Hobot JA, Kellenberger E, Villiger W (1982) Specimen preparation for electron microscopy using low temperature embedding resins. J Microsc 26: 77–85Google Scholar
  9. 9.
    Roth J, Bendayan M, Orci L (1978) Ultrastructural localization of intracellular antigens by the use of protein A-gold complex. J Histochem Cytochem 26: 1074–1081Google Scholar
  10. 10.
    Worwood M, Dodgson KS, Hook GER, Rose FA (1973) Problems associated with the assay of arylsulfatases A and B of rat tissues. Biochem J 134: 183–190Google Scholar
  11. 11.
    Schlichtkrull J (1961) Insulin Crystals. Thesis, University of Copenhagen, DenmarkGoogle Scholar
  12. 12.
    Laemmli UK (1970) Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227: 680–685Google Scholar
  13. 13.
    Emdin SO, Dodson GG, Cutfield JM, Cutfield SM (1974) Role of zinc in insulin biosynthesis. Diabetologia 19: 174–182Google Scholar
  14. 14.
    Grant PT, Coombs TL, Frank BH (1972) Differences in the nature of the interaction of insulin and proinsulin with zinc. Biochem J 126: 433–440Google Scholar
  15. 15.
    Blundell T, Dodson G, Hodgkin D, Mercola D (1972) Insulin: the structure in the crystal and its reflection in chemistry and biology. Adv Protein Chem 26: 279–402Google Scholar
  16. 16.
    Hutton JC (1982) The internal pH and membrane potential of the insulin-secretory granules. Biochem J 204: 171–178Google Scholar
  17. 17.
    Orci L (1985) The insulin factory: a tour of the plant surroundings and a visit to the assembly line. Diabetologia 28: 528–546Google Scholar
  18. 18.
    Ravazzola M, Malaisse-Lagae F, Amherdt M, Perrelet A, Malaisse WJ, Orci L (1976) Patterns of calcium localization in pancreatic endocrine cells. J Cell Sci 21: 107–118Google Scholar
  19. 19.
    Hutton JC, Penn EJ, Peshavaria M (1983) Low-molecular-weight constituents of isolated insulin-secretory granules. Biochem J 210: 297–305Google Scholar
  20. 20.
    Coore HG, Hellman B, Pihl E, Täljedal I-B (1969) Physiochemical characteristics of insulin secretion granules. Biochem J 111: 107–113Google Scholar
  21. 21.
    Howell SL, Tyhurst M, Duvefelt H, Andersson A, Hellerstrom C (1978) Role of zinc and calcium in the formation and storage of insulin in the pancreatic β-cell. Cell Tiss Res 188: 107–118Google Scholar
  22. 22.
    Roos A, Boron WF (1981) Intracellular pH. Physiological Reviews 61: 296–403Google Scholar
  23. 23.
    Ohkuma S, Poole B (1978) Fluorescence probe measurement of the intralysosomal pH in living cells and the perturbation of pH by various agents. Proc Natl Acad Sci 75: 3327–3331Google Scholar
  24. 24.
    Reijingoud D-J, Tager JM (1977) The permeability properties of the lysosomal membrane. Biochimica et Biophysica Acta 472: 419–449Google Scholar
  25. 25.
    Greider MH, Howell SL, Lacy PE (1969) Isolation and properties of secretory granules from rat islets of Langerhans. II. Ultrastructure of the beta granule. J Cell Biol 41: 162–166Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • P. A. Halban
    • 1
    • 4
  • R. Mutkoski
    • 1
  • G. Dodson
    • 2
  • L. Orci
    • 3
  1. 1.Research Division, Joslin Diabetes Center, and Department of MedicineBrigham and Women's Hospital, Harvard Medical SchoolBostonUSA
  2. 2.Department of ChemistryUniversity of YorkUK
  3. 3.Institute of Histology and EmbryologyUniversity of Geneva School of MedicineGenevaSwitzerland
  4. 4.Unité JeantetCentre Médical UniversitaireGeneva 4Switzerland

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