Real-time measurement of F-actin remodelling during exocytosis using Lifeact-EGFP transgenic animals

PLoS One. 2012;7(7):e39815. doi: 10.1371/journal.pone.0039815. Epub 2012 Jul 2.


F-actin remodelling is essential for a wide variety of cell processes. It is important in exocytosis, where F-actin coats fusing exocytic granules. The purpose of these F-actin coats is unknown. They may be important in stabilizing the fused granules, they may play a contractile role and promote expulsion of granule content and finally may be important in endocytosis. To elucidate these functions of F-actin remodelling requires a reliable method to visualize F-actin dynamics in living cells. The recent development of Lifeact-EGFP transgenic animals offers such an opportunity. Here, we studied the characteristics of exocytosis in pancreatic acinar cells obtained from the Lifeact-EGFP transgenic mice. We show that the time-course of agonist-evoked exocytic events and the kinetics of each single exocytic event are the same for wild type and Lifeact-EGFP transgenic animals. We conclude that Lifeact-EGFP animals are a good model to study of exocytosis and reveal that F-actin coating is dependent on the de novo synthesis of F-actin and that development of actin polymerization occurs simultaneously in all regions of the granule. Our insights using the Lifeact-EGFP mice demonstrate that F-actin coating occurs after granule fusion and is a granule-wide event.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / genetics
  • Actins / metabolism*
  • Animals
  • Cells, Cultured
  • Exocytosis / physiology*
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism*
  • Mice
  • Mice, Transgenic
  • Microscopy, Confocal / methods
  • Pancreas / cytology*
  • Pancreas / metabolism*
  • Secretory Vesicles / genetics
  • Secretory Vesicles / metabolism


  • Actins
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins