Identification of Proteins Required for Ca2+-Triggered Secretion

  • Thomas F. J. Martin
  • Jane H. Walent
  • Bruce W. Porter
  • Jesse C. Hay


Eukaryotic cells synthesize proteins whose final destinations are the extracellular space, the plasma membrane or intracellular organelles. The constitutive secretory pathway employed to sort proteins consists of a series of inter-organelle transport steps that are vesicle-mediated. The cellular mechanisms employed in this pathway are under active investigation since such studies promise to reveal insights into the poorly understood biochemical events involved in vesicle budding, vesicle targeting and membrane fusion. Individual vesicle transport steps of the constitutive pathway from the endoplasmic reticulum to plasma membrane fusion have been successfully reconstituted in semi-intact cells or in homogenates.1 These in vitro reactions typically exhibit a requirement for ATP and cytosolic proteins2, and several cytosolic proteins have been purified and characterized, including the 76 kD NSF protein, 35–39 kD SNAP proteins, a 25 kD POP protein, low molecular weight GTP-binding proteins, and components of a non-clathrin coat.3,4 Genetic approaches in Saccharomyces cerevisiae have complemented the in vitro reconstitution approach, and a large number of genes required in the yeast secretory pathway have been identified by mutational analysis.5 Although the biochemical events underlying membrane fusion have eluded detailed description thus far, the identification of several key protein participants represents an important step toward this goal.


Cell Ghost Botulinum Neurotoxin Cytosolic Factor Regulate Secretion Dense Core Granule 
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  1. 1.
    Rothman JE, Orci, L. Molecular dissection of the secretory pathway. Nature 1992; 355: 409.PubMedCrossRefGoogle Scholar
  2. 2.
    Goda Y, Pfeffer, SR. Cell-free systems to study vesicular transport along the secretory and endocytic pathways. FASEB J 1989; 3: 2488.Google Scholar
  3. 3.
    Wilson DW, Whiteheart SW, Orci L, Rothman JE. Intracellular membrane fusion. Trends Biochem Sci 1991; 16: 334.PubMedCrossRefGoogle Scholar
  4. 4.
    Rothman JE, Orci L. Movement of proteins through the Golgi stack: a molecular dissection of vesicular transport. FASEB J 1990; 4: 1460.PubMedGoogle Scholar
  5. 5.
    Hicke L, Schekman R. Molecular machinery required for protein transport from the endoplasmic reticulum to the Golgi complex. BioEssays 1990; 12: 253.PubMedCrossRefGoogle Scholar
  6. 6.
    Burgess TL, Kelly RB. Constitutive and regulated secretion of proteins. Ann Rev Cell Biol 1987; 3: 243.PubMedCrossRefGoogle Scholar
  7. 7.
    Tooze SA, Weiss U, Huttner WB. A requirement for GTP hydrolysis in the formation of secretory vesicles. Nature 1990; 347: 207.PubMedCrossRefGoogle Scholar
  8. 8.
    Miller SG, Moore H-PH. Reconstitution of constitutive secretion using semi-intact cells: regulation by GTP but not calcium. J Cell Biol 1991; 112: 39.PubMedCrossRefGoogle Scholar
  9. 9.
    Turkewitz AP, Madeddu L, Kelly RB. Maturation of dense core granules in wild type and mutant Tetrahymena thermophila. EMBO J 1991; 10: 1979.PubMedGoogle Scholar
  10. 10.
    Peppers SC, Holz RW. Catecholamine secretion from digitonin-treated PC12 cells. J Biol Chem 1986; 261: 14665.PubMedGoogle Scholar
  11. 11.
    Sarafian T, Aunis D, Bader M-F. Loss of proteins from digitonin-permeabilized adrenal chromaffin cells essential for exocytosis. J Biol Chem 1987; 262: 16671.PubMedGoogle Scholar
  12. 12.
    Koffer A, Gomperts BD. Soluble proteins as modulators of the exocytotic reaction of pemieabilized rat mast cells. J Cell Sci 1989; 94: 585.PubMedGoogle Scholar
  13. 13.
    Martin TFJ. Cell cracking: permeabilizing cells to macromolecular probes. Meth Enzymol 1989; 168: 225.PubMedCrossRefGoogle Scholar
  14. 14.
    Martin TFJ, Walent JH. A new method for cell permeabilization reveals a cytosolic protein requirement for Cat+-activated secretion in GH3 pituitary cells. J Biol Chem 1989; 264: 10299.PubMedGoogle Scholar
  15. 15.
    Lomneth R, Martin TFJ, DasGupta BR. Botulinum neurotoxin light chain inhibits norepinephrine secretion in PC12 cells at an intracellular membranous or cytoskeletal site. J Neurochem 1991; 57: 1413.PubMedCrossRefGoogle Scholar
  16. 16.
    Walent JH, Porter BW, Martin TFJ. A novel 145 kD brain cytosolic protein reconstitutes Cat+-regulated secretion in permeable neuroendocrine cells. Cell 1992 (in press).Google Scholar
  17. 17.
    Nishizaki T, Walent JH, Kowalchyk JA, Martin TFJ. A key role for p145 in the stimulation of Calf-dependent secretion by protein kinase C. J Biol Chem 1992 (in press).Google Scholar
  18. 18.
    Hay JC, Martin TFJ. Resolution of regulated secretion into sequential MgATP-dependent and Cat+-dependent stages mediated by distinct cytosolic proteins. J Cell Biol 1992 (in press).Google Scholar
  19. 19.
    Pimplikar SW, Huttner WB. Chromogranin B (Secretogranin I), a secretory protein of the regulated pathway, is also present in a tightly membrane-associated form in PC12 cells. J Biol Chem 1992; 267: 4110.PubMedGoogle Scholar
  20. 20.
    Augustine GJ, Neher E. Calcium requirements for secretion in bovine chromaffin cells. J Physiol, in press.Google Scholar
  21. 21.
    Eberhard DE, Cooper CL, Low MG, Holz, RW. Evidence that the inositol phospholipids are necessary for exocytosis. Biochem J 1990; 268: 15.PubMedGoogle Scholar
  22. 22.
    Wagner PD, Vu N-D. Regulation of norepinephrine secretion in permeabilized PC12 cells by Cat+-stimulated phosphorylation. J Biol Chem 1990; 265: 10352.PubMedGoogle Scholar
  23. 23.
    Howell TW, Kramer IM, Gomperts BD. Protein phosphorylation and the dependence on Cat+ and GTP-y-S for exocytosis from permeabilized mast cells. Cellular Signalling 1989; 1: 157.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1993

Authors and Affiliations

  • Thomas F. J. Martin
    • 1
  • Jane H. Walent
    • 1
  • Bruce W. Porter
    • 1
  • Jesse C. Hay
    • 1
  1. 1.Department of ZoologyUniversity of WisconsinMadisonUSA

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