G3BP-1: an hnRNA-binding protein and endoribonuclease that participates in the Ras signal transduction pathway. A regulated effector of stress granule (SG) assembly. SGs are involved in mRNA sorting in the storing of untranslated mRNAs. Cleaves exclusively between cytosine and adenine and cleaves MYC mRNA preferentially at the 3'-UTR. ATP- and magnesium-dependent helicase. Unwinds preferentially partial DNA and RNA duplexes having a 17 bp annealed portion and either a hanging 3' tail or hanging tails at both 5'- and 3'-ends. Unwinds DNA/DNA, RNA/DNA, and RNA/RNA substrates with comparable efficiency. Acts unidirectionally by moving in the 5' to 3' direction along the bound single-stranded DNA. Binds to the SH3 domain of Ras GTPase-activating protein (RasGAP) in proliferating cells but not in quiescent cells. Cytoplasmic in proliferating cells, can be recruited to the plasma membrane in exponentially growing cells. Cytosolic and partially nuclear in resting cells. Recruited to SGs upon either arsenite or high temperature treatment. RasGAP-dependent phosphorylation of S149 induces a conformational change that prevents self-association. Dephosphorylation after HRAS activation is required for stress granule assembly. S149 phosphorylation induces partial nuclear localization. A component of a TAU mRNP complex, Interacts with USP10, and may regulate it.
Protein type: EC 3.6.4.12; RNA-binding; Helicase; Adaptor/scaffold; EC 3.6.4.13
Chromosomal Location of Human Ortholog: 5q33.1
Cellular Component: focal adhesion; stress granule; cytoplasm; plasma membrane; cytosol; nucleus
Molecular Function: mRNA binding; ATP-dependent DNA helicase activity; protein binding; DNA binding; endonuclease activity; ATP-dependent RNA helicase activity; ATP binding
Biological Process: transport; metabolic process; Ras protein signal transduction; DNA duplex unwinding
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