Related Experiment Video
Updated: Aug 31, 2026

Probing Structural and Dynamic Properties of Trafficking Subcellular Nanostructures by Spatiotemporal Fluctuation Spectroscopy
Published on: August 16, 2021
Spatiotemporal dynamics of the COPI vesicle machinery
Markus Elsner1, Hitoshi Hashimoto, Jeremy C Simpson
1Cell Biology and Cell Biophysics Programme, EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
Abstract:
Assembly of the coat protein I (COPI) vesicle coat is controlled by the small GTPase ADP ribosylation factor 1 (ARF1) and its GTPase-activating protein, ARFGAP1. Here, we investigate the diffusional behaviours of coatomer, the main component of the coat, and also those of ARF1 and ARFGAP1. Using fluorescence-correlation spectroscopy, we found that most ARF1 and ARFGAP1 molecules are highly mobile in the cytosol (diffusion constant D approximately equal to 15 microm(2) s(-1)), whereas coatomer diffuses 5-10 times more slowly than expected (D approximately equal to 1 microm(2) s(-1)). This slow diffusion causes diffusion-limited binding kinetics to Golgi membranes, which, in FRAP (fluorescence recovery after photobleaching) experiments, translates into a twofold slower binding rate. The addition of aluminium fluoride locks coatomer onto Golgi membranes and also decreases the binding kinetics of both ARF1 and ARFGAP1, suggesting that these proteins function in concert to mediate sorting and vesicle formation.
Related Concept Videos
Vesicular Tubular Clusters
With the help of motor proteins such...
Pinching-off of Coated Vesicles
COP Coated Vesicles
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Fusion of Secretory Vesicles with the Plasma Membrane
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
Overview of Secretory Vesicles
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...

