First published online December 20, 2007
Journal of Cell Science 121, 103e (2008)
© The Company of Biologists Limited
ERES keep their distance
Proteins destined for secretion are usually first transported from the ER to the Golgi complex, where they are post-translationally modified. Transport is mediated by COPII-coated vesicles, which form when COPII proteins bind at endoplasmic reticulum exit sites (ERES) and self-assemble into clusters. The size of individual ERES varies widely between closely related organisms, but the factors that govern cluster size and ERES location are not known. On page 55, Matthias Weiss and colleagues model ERES formation using a set of basic assumptions about COPII attachment, diffusion and turnover. The authors show that simulated ERES-like clusters tend to `keep their distance' from one another, forming a quasi-crystalline array of relatively evenly spaced clusters that is similar to the pattern seen in cells. Moreover, the broad size distribution of clusters predicted by the model also echoes the spread of ERES size in vivo. On the basis of their model, the authors predict that ERES size depends on the rate of COPII-protein turnover. Differences in turnover rate could therefore explain the observed interspecies differences in ERES size.
Related articles in JCS:
- A model for the self-organization of exit sites in the endoplasmic reticulum
- Stephan Heinzer, Stefan Wörz, Claudia Kalla, Karl Rohr, and Matthias Weiss
JCS 2008 121: 55-64.
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