Cell Biology

Letting Ras Know Where It's At

Science's STKE  22 Mar 2005:
Vol. 2005, Issue 276, pp. tw112
DOI: 10.1126/stke.2762005tw112

The correct spatial organization of cellular signaling molecules is crucial to ensuring proper biological response. Some signaling proteins, such as the Ras guanosine triphosphatases, are modified by lipids that direct their localization to the plasma membrane and to intracellular membranes of the Golgi complex. Ras proteins are thought to acquire these lipid moieties while transiting through the secretory pathway. Rocks et al. (see the Perspective by Meder and Simons) now find that Ras becomes depalmitoylated at the plasma membrane, releasing the protein to the cytoplasm. Released Ras that is redistributed to the Golgi becomes repalmitoylated and subsequently transported to the cell surface, where the acylation cycle begins again. These changes in palmitoylation correlate with Ras signaling and provide a mechanism for controlling Ras protein intracellular distribution.

O. Rocks, A. Peyker, M. Kahms, P. J. Verveer, C. Koerner, M. Lumbierres, J. Kuhlmann, H. Waldmann, A. Wittinghofer, P. I. H. Bastiaens, An acylation cycle regulates localization and activity of palmitoylated Ras isoforms. Science 307, 1746-1752 (2005). [Abstract] [Full Text]

D. Meder, K. Simons, Ras on the roundabout. Science 307, 1731-1733 (2005). [Summary] [Full Text]