Ras GTPases undergo post-translational modifications that govern their subcellular trafficking and localization. In particular, palmitoylation of the Golgi tags N-Ras and H-Ras for exocytotic transport and residency at the PM (plasma membrane). Following depalmitoylation, PM-Ras redistributes to all subcellular membranes causing an accumulation of palmitate-free Ras at endomembranes, including ...

Ras proteins transduce signals from membrane-bound receptors via multiple downstream effector pathways and thereby affect fundamental cellular processes, including proliferation, apoptosis, and differentiation. K-ras activating mutations play a key role in neoplastic progression and are particularly prevalent in colorectal, pancreatic, and lung cancers. The present study addressed whether the K...

PURPOSE Activation of the RAS pathway plays a major role in cancer cells. In acute myeloid leukemia (AML), mutations of the RAS genes cause an intrinsic activation of this pathway. Until now, clinical studies could not find clear association of RAS mutations with the clinical outcome after AML therapy. This could be due to alternative initiating events for activation of the RAS pathway like con...

In mammals, the three classical ras genes encode four highly homologous proteins, N-Ras, H-Ras, and the isoforms K-Ras 4A and 4B. Previous studies have shown that K-ras is essential for mouse development and that while K-ras 4A and 4B are expressed during development, K-ras 4A expression is regulated temporally and spatially and occurs in adult kidney, intestine, stomach, and liver. In the pres...

Exclusive activation of either the Harvey-, Kirsten-, or N-ras gene is often found in human and rodent cancers, although the mechanisms responsible for tissue-specific ras gene activation are poorly understood. In this study, the contribution of ras gene expression and Ras protein activity to the tissue-specificity of ras gene activation was investigated using the rat mammary carcinogenesis mod...

Ras expression has been suggested as a marker for tumor aggressiveness of breast cancer,including the degrees of invasion and tumor recurrence.We showed previously that H-ras, but not N-ras, up-regulates matrix metalloproteinase 2 expression and induces invasive phenotype in MCF10A human breast epithelial cells (A. Moon, et al. Int. J. Cancer, 85: 176-181, 2000). In this study, we show that H-r...

STP-C488 (STP of herpesvirus saimiri [HVS] group C strain 488 [C488]) is the only virus-encoded protein found to associate with cellular ras and activate ras signal transduction pathways. To investigate an important role for ras signal transduction in STP-dependent growth transformation, we constructed recombinant strains of HVS C488 in which the STP-C488 oncogene was replaced with cellular nor...