Muscle RAS Oncogene Homolog (MRAS)

Mras contains motifs for GDP/GTP binding and a C-terminal motif that mediates membrane attachment by a geranylgeranyl group in combination with a polybasic region. Northern blot analysis detected transcripts of 4.2 and 1.7 kb in mouse brain and in mouse myoblast cell line C2. Expression of the 4.2-kb transcript was high in brain and low in C2 myoblasts, whereas expression of the 1.7-kb transcript was low in both brain and C2 myoblasts. RT-PCR detected expression of mouse Mras in C2 myotubes, fibroblasts, skeletal muscle, heart, and uterus. Epitope-tagged Mras was expressed in mouse fibroblasts on plasma membrane-associated structures, including microspikes, membrane ruffles, and pseudopods. It was also diffusely distributed throughout the cytoplasm.