Cell Biology

A Multitasking Network

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Science  25 Aug 2000:
Vol. 289, Issue 5483, pp. 1257
DOI: 10.1126/science.289.5483.1257b

The endoplasmic reticulum (ER) is a dynamic arrangement of intracellular membrane representing the entry portal to the protein secretory pathway. Much is known about the architecture of the ER in mammalian cells, but the structure and dynamics of the yeast ER are less well understood due to the difficulty of visualizing subcellular structures in very small cells.

With the aid of a fluorescently tagged ER membrane protein, Prinz et al. observed in vivo a dynamic ER located in the periphery of the yeast cytoplasm. Unlike mammalian ER, maintenance of this network in yeast did not require intact microtubules, although actin did appear to be important for ER dynamics. Mutations in proteins involved in membrane traffic out of the ER (to the Golgi) and mutations in proteins required for targeting ribosomes to the ER (the SRP pathway) did affect network structure. Disturbance of the ER morphology also perturbed in parallel yeast mitochondrial structure, indicating that mitochondria may utilize the ER network as a scaffold for their own reticular organization. — SMH

J. Cell Biol.150, 461 (2000).

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