A typical eukaryotic cell contains many types of membrane organelles with characteristic distributions within the cytoplasm. This distribution is facilitated in part by the organelle binding to a specific subset of motor proteins. Bound motors then transport the organelles to their proper destinations in the cell by moving them along microtubules or actin filaments. A key question of modern cell biology is how motor proteins recognize their target organelles. A number of recent articles address this question by showing that Rab proteins on the surface of organelles can function as a part of the recognition complex for motor proteins.
Rab proteins form the largest branch of the Ras superfamily of GTPases. They are found in organisms from yeast to human, and have been implicated in various functions within the cell including growth, protein trafficking, and the targeting and fusion...
