A potential p120 GTPase-activating protein (RasGAP) effector, G3BP (RasGAP Src homology 3 [SH3] binding protein), was previously identified based on its ability to bind the SH3 domain of RasGAP. Here we show that G3BP colocalizes and physically interacts with RasGAP at the plasma membrane of serum-stimulated but not quiescent Chinese hamster lung fibroblasts. In quiescent cells, G3BP was hyperphosphorylated on serine residues, and this modification was essential for its activity. Indeed, G3BP harbors a phosphorylation-dependent RNase activity which specifically cleaves the 3'-untranslated region of human c-myc mRNA. The endoribonuclease activity of G3BP can initiate mRNA degradation and therefore represents a link between a RasGAP-mediated signaling pathway and RNA turnover.
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http://dx.doi.org/10.1128/MCB.18.7.3956 | DOI Listing |
J Cell Biol
November 2023
Institut de Génétique Moléculaire de Montpellier, UMR 5535 du Centre National de la Recherche Scientifique (CNRS), Université Montpellier, Montpellier, France.
Stress granules (SGs) are formed in the cytoplasm in response to various toxic agents and are believed to play a critical role in the regulation of mRNA metabolism during stress. In SGs, mRNAs are stored in an abortive translation initiation complex that can be routed to either translation initiation or degradation. Here, we show that G3BP, a phosphorylation-dependent endoribonuclease that interacts with RasGAP, is recruited to SGs in cells exposed to arsenite.
View Article and Find Full Text PDFActa Crystallogr D Struct Biol
November 2022
Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany.
Small nuclear ribonucleoprotein complexes (snRNPs) represent the main subunits of the spliceosome. While the assembly of the snRNP core particles has been well characterized, comparably little is known of the incorporation of snRNP-specific proteins and the mechanisms of snRNP recycling. U5 snRNP assembly in yeast requires binding of the the Aar2 protein to Prp8p as a placeholder to preclude premature assembly of the SNRNP200 helicase, but the role of the human AAR2 homolog has not yet been investigated in detail.
View Article and Find Full Text PDFFront Immunol
February 2022
University of Alabama at Birmingham (UAB) Research Center of Excellence in Arsenicals, Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL, United States.
The use of chemical warfare agents is prohibited but they have been used in recent Middle Eastern conflicts. Their accidental exposure (e.g.
View Article and Find Full Text PDFCell Rep
December 2021
Department of Cell Biology, Key Laboratory of Cell Biology, National Health Commission of the PRC and Key Laboratory of Medical Cell Biology, Ministry of Education of the PRC, China Medical University, No. 77, Puhe Road, Shenyang North New Area, Shenyang, Liaoning 110122, China. Electronic address:
P21-activated kinase 5 (PAK5) plays an important role in tumors. However, the functional role of PAK5 in mammary tumorigenesis in vivo remains unclear. Here, we show that PAK5 deficiency represses MMTV-PyVT-driven breast tumorigenesis.
View Article and Find Full Text PDFInt J Biol Sci
March 2022
Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China; Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological Disorders, Wuhan, 430030, PR China.
Chronic diabetes accelerates vascular dysfunction often resulting in cardiomyopathy but underlying mechanisms remain unclear. Recent studies have shown that the deregulated unfolded protein response (UPR) dependent on highly conserved IRE1α-spliced X-box- binding protein (XBP1s) and the resulting endoplasmic reticulum stress (ER-Stress) plays a crucial role in the occurrence and development of diabetic cardiomyopathy (DCM). In the present study, we determined whether targeting MAPK/ERK pathway using MEK inhibitor U0126 could ameliorate DCM by regulating IRE1α-XBP1s pathway.
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