The endoplasmic reticulum (ER) is a dynamic, interconnected network of membrane vesicles, cisternae (sac-like structures), and tubules. The ER serves many functions, including protein synthesis (on the rough ER), protein folding, and protein sorting. The ER experiences complex rearrangements, and a recent paper identifies Rab10 as a regulator of these ER dynamics. Rab10 is a Rab GTPase, a family of membrane proteins that function as molecular switches for many membrane-based events such as vesicle formation and fusion. English and Voeltz found that Rab10 is found on the ER and on ER-structures involved in new ER tubule growth. Depletion of Rab10, or expression of a mutant Rab10, caused a disruption of ER morphology, as well as reduced ER tubule extension and fusion. In the images above, cells were labeled with an ER marker. Compared to controls cells, Rab10-depleted cells had an altered ER morphology, notably more expansive cisternae and fewer tubules.
English, A., & Voeltz, G. (2012). Rab10 GTPase regulates ER dynamics and morphology Nature Cell Biology, 15 (2), 169-178 DOI: 10.1038/ncb2647
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