Proteins on the Move Endosomes Get a Tail
Intracellular bacteria, such as Listeria, use actin tails to propel themselves through the cytoplasm. Clearly the bacteria have highjacked the cell's actin-polymerization machinery. But, based on the observations of Taunton et al. that cells make their own actin-rich tails Taunton et al. (page 519), Listeria appear to have hijacked the idea not just of polymerization, but also of tail formation. Taunton et al. characterize endosomal vesicles that move in Xenopus oocytes and extracts using such tails.
At least in extracts, the vesicles are identified as endosomes based on their multivesicular structure and staining with acridine orange. Endosomal membranes from HeLa cells move when added to extracts, whereas plasma and endoplasmic reticulum membranes do not. Purified Golgi membranes may yet show motile activity, as Cdc42 has been shown to have...
