Number of Ras molecules in cytoplasm

Value 240000 molecules/cell
Organism Human Homo sapiens
Reference Fujioka A, Terai K, Itoh RE, Aoki K, Nakamura T, Kuroda S, Nishida E, Matsuda M: Dynamics of the Ras/ERK MAPK cascade as monitored by fluorescent probes. J Biol Chem 2006, 281:8917-8926. p.8919 table 1PubMed ID16418172
Method Abstract: "To comprehend the Ras/ERK MAPK cascade, which comprises Ras, Raf, MEK, and ERK, several kinetic simulation models have been developed. However, a large number of parameters that are essential for the development of these models are still missing and need to be set arbitrarily. Here, [investigators] aimed at collecting these missing parameters using fluorescent probes. First, the levels of the signaling molecules were quantitated. Second, to monitor both the activation and nuclear translocation of ERK, [they] developed probes based on the principle of fluorescence resonance energy transfer. Third, the dissociation constants of Ras•Raf, Raf•MEK, and MEK•ERK complexes were estimated using a fluorescent tag that can be highlighted very rapidly. Finally, the same fluorescent tag was used to measure the nucleocytoplasmic shuttling rates of ERK and MEK. Using these parameters, [they] developed a kinetic simulation model consisting of the minimum essential members of the Ras/ERK MAPK cascade. This simple model reproduced essential features of the observed activation and nuclear translocation of ERK. In this model, the concentration of Raf significantly affected the levels of phospho-MEK and phospho-ERK upon stimulation. This prediction was confirmed experimentally by decreasing the level of Raf using the small interfering RNA technique. This observation verified the usefulness of the parameters collected in this study." Calculated from concentration of Ras in cytoplasm=0.4µM Average volume of cytoplasm=1pL Number Ras proteins=[Ras]*vol*6.02E23 = 2.4×10^5
Comments Compare value of 1.14E7 RAS-GDP molecules/cell measured by Biochemical quantification in 2002 BNID 104828 Table - link
Entered by Ariosto Silva
ID 104826