RasGAP-Associated Endoribonuclease G3BP: Selective RNA Degradation and Phosphorylation-Dependent Localization

AUTOR(ES)

Tourrière, Hélène

FONTE

American Society for Microbiology

RESUMO

Mitogen activation of mRNA decay pathways likely involves specific endoribonucleases, such as G3BP, a phosphorylation-dependent endoribonuclease that associates with RasGAP in dividing but not quiescent cells. G3BP exclusively cleaves between cytosine and adenine (CA) after a specific interaction with RNA through the carboxyl-terminal RRM-type RNA binding motif. Accordingly, G3BP is tightly associated with a subset of poly(A)+ mRNAs containing its high-affinity binding sequence, such as the c-myc mRNA in mouse embryonic fibroblasts. Interestingly, c-myc mRNA decay is delayed in RasGAP-deficient fibroblasts, which contain a defective isoform of G3BP that is not phosphorylated at serine 149. A G3BP mutant in which this serine is changed to alanine remains exclusively cytoplasmic, whereas a glutamate for serine substitution that mimics the charge of a phosphorylated serine is translocated to the nucleus. Thus, a growth factor-induced change in mRNA decay may be modulated by the nuclear localization of a site-specific endoribonuclease such as G3BP.

Documentos Relacionados

• p190 RhoGAP, the major RasGAP-associated protein, binds GTP directly.
• A Novel Phosphorylation-Dependent RNase Activity of GAP-SH3 Binding Protein: a Potential Link between Signal Transduction and RNA Stability
• Phosphorylation-dependent Localization of Microtubule-associated Protein MAP2c to the Actin CytoskeletonV⃞
• Phosphorylation-dependent ubiquitylation and degradation of androgen receptor by Akt require Mdm2 E3 ligase
• Chk2 Activation and Phosphorylation-Dependent Oligomerization