Getting it on - GDI displacement and small GTPase membrane recruitment

Understanding the mechanisms by which signaling events are localized and the physiological consequences of spatial restriction are major questions in cell biology. A recent issue of Nature reports the identification of an endosomal factor that can directly recruit Rab GTPases from the cytosol onto membranes (Sivars et al., 2003). Together with work describing the structure of prenylRab with Rab-GDI (Rak et al., 2003), this provides us both with new avenues and important insights into long-standing questions of Rab GTPase signaling and membrane traffic.