Fusion of secretory vesicles isolated from rat liver

Manfred Gratzl, Gerhard Dahl

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Secretory vesicles isolated from rat liver were found to fuse after exposure to Ca2+. Vescle fusion is characterized by the occurrence of twinned vesicles with a continuous cleavage plane between two vesicles in freeze-fracture electron microscopy. The number of fused vesicles increases with increasing Ca2+-concentrations and is half maximal around 10-6m. Other divalent cations (Ba2+, Sr2+, and Mg2+) were ineffective. Mg2+ inhibits Ca2+-induced fusion. Therefore, the fusion of secretory vesicles in vitro is Ca2+ specific and exhibits properties similar to the exocytotic process of various secretory cells. Various substances affecting secretion in vivo (microtubular inhibitors, local anethetics, ionophores) were tested for their effect on membrane fusion in our system. The fusion of isolated secretory vesicles from liver was found to differ from that of pure phospholipid membranes in its temperature dependence, in its much lower requirement for Ca2+, and in its Ca2+-specificity. Chemical and enzymatic modifications of the vesicle membrane indicate that glycoproteins may account for these differences.

Original languageEnglish
Pages (from-to)343-364
Number of pages22
JournalThe Journal of Membrane Biology
Volume40
Issue number4
DOIs
StatePublished - Dec 1 1978
Externally publishedYes

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Secretory Vesicles
Liver
Membrane Fusion
Secretory Pathway
Ionophores
Membrane Glycoproteins
Divalent Cations
Phospholipids
Electron Microscopy
Temperature
Membranes

ASJC Scopus subject areas

  • Physiology
  • Cell Biology
  • Biophysics

Cite this

Fusion of secretory vesicles isolated from rat liver. / Gratzl, Manfred; Dahl, Gerhard.

In: The Journal of Membrane Biology, Vol. 40, No. 4, 01.12.1978, p. 343-364.

Research output: Contribution to journalArticle

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