RRC ID 49235
著者 Yoshizawa R, Umeki N, Yanagawa M, Murata M, Sako Y.
タイトル Single-molecule fluorescence imaging of RalGDS on cell surfaces during signal transduction from Ras to Ral.
ジャーナル Biophys Physicobiol
Abstract RalGDS is one of the Ras effectors and functions as a guanine nucleotide exchange factor for the small G-protein, Ral, which regulates membrane trafficking and cytoskeletal remodeling. The translocation of RalGDS from the cytoplasm to the plasma membrane is required for Ral activation. In this study, to understand the mechanism of Ras-Ral signaling we performed a single-molecule fluorescence analysis of RalGDS and its functional domains (RBD and REMCDC) on the plasma membranes of living HeLa cells. Increased molecular density of RalGDS and RBD, but not REMCDC, was observed on the plasma membrane after EGF stimulation of the cells to induce Ras activation, suggesting that the translocation of RalGDS involves an interaction between the GTP-bound active form of Ras and the RBD of RalGDS. Whereas the RBD played an important role in increasing the association rate constant between RalGDS and the plasma membrane, the REMCDC domain affected the dissociation rate constant from the membrane, which decreased after Ras activation or the hyperexpression of Ral. The Y64 residue of Ras and clusters of RalGDS molecules were involved in this reduction. From these findings, we infer that Ras activation not merely increases the cell-surface density of RalGDS, but actively stimulates the RalGDS-Ral interaction through a structural change in RalGDS and/or the accumulation of Ral, as well as the GTP-Ras/RalGDS clusters, to induce the full activation of Ral.
巻・号 14
ページ 75-84
公開日 2017-6-1
DOI 10.2142/biophysico.14.0_75
PII 14_75
PMID 28744424
PMC PMC5515350
引用数 5
リソース情報
遺伝子材料 Genome Network Project Human cDNA IRAK084F17 (HGX033737)