The Ras superfamily is a fascinating example of functional diversification in the context of a preserved structural framework and a prototypic GTP binding site. Thanks to the availability of complete genome sequences of species representing important evolutionary branch points, we have analyzed the composition and organization of this superfamily at a greater level than was previously possible....

Smad7 and Smad6 are inhibitory Smads that block transforming growth factor-beta (TGF-beta) superfamily signal transduction. Smad7 is overexpressed in chemically induced mouse epidermal tumors, where oncogenic activation of c-ras is a frequent event. To test the role of Smad7 overexpression in tumor progression, we used retroviruses to transduce Smad7 or Smad6 and v-ras(Ha) into primary mouse ke...

The Ras superfamily consists of a large group of monomeric GTPases demonstrating homology to Ras oncoproteins. Although structurally similar, Ras-superfamily proteins are functionally diverse. Whereas some members exhibit oncogenic properties, others may serve as tumor suppressors. We have identified a novel Ras-related protein that suppresses cell growth and have designated it Rig (Ras-related...

Ras proteins function as signaling hubs that are activated by convergent signaling pathways initiated by extracellular stimuli. Activated Ras in turn regulates a diversity of downstream cytoplasmic signaling cascades. Ras proteins are founding members of a large superfamily of small GTPases that have significant sequence and biochemical similarities. Recent observations have established a compl...

a new article published in the journal Aging, Borras et al. report that Ras-GRF1 homozigous deletion increases both median and maximum longevity in laboratory mice [1]. The human Ras, superfamily now counts more than 150 different proteins subdivided into five different protein families: Ras, Rho, Rab, Arf and Ran. These protein families regulate many cellular processes [2] including cellular d...

Members of the protein superfamily of small guanosine triphosphatases, also known as small GTPases, small G-proteins, or the Ras superfamily, are involved in nearly every aspect of cell biology. Small GTPases are tightly regulated molecular switches that make binary on/off decisions through controlled loading of GTP (activation) and hydrolysis of GTP to GDP (inactivation). Small GTPases typical...

The Ras superfamily of small guanosine triphosphatases (GTPases) comprise over 150 human members (Table S1 in supplementary material), with evolutionarily conserved orthologs found in Drosophila, C. elegans, S. cerevisiae, S. pombe, Dictyostelium and plants (Colicelli, 2004). The Ras oncogene proteins are the founding members of this family, which is divided into five major branches on the basi...