G3BP1

This gene encodes one of the DNA-unwinding enzymes which prefers partially unwound 3'-tailed substrates and can also unwind partial RNA/DNA and RNA/RNA duplexes in an ATP-dependent fashion. This enzyme is a member of the heterogeneous nuclear RNA-binding proteins and is also an element of the Ras signal transduction pathway. It binds specifically to the Ras-GTPase-activating protein by associating with its SH3 domain. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.

Full Name

G3BP1

Function

ATP- and magnesium-dependent helicase that plays an essential role in innate immunity (PubMed:30510222).

Participates in the DNA-triggered cGAS/STING pathway by promoting the DNA binding and activation of CGAS. Enhances also DDX58-induced type I interferon production probably by helping DDX58 at sensing pathogenic RNA (PubMed:30804210).

In addition, plays an essential role in stress granule formation (PubMed:12642610, PubMed:20180778, PubMed:23279204).

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 (PubMed:9889278).

Unwinds DNA/DNA, RNA/DNA, and RNA/RNA substrates with comparable efficiency (PubMed:9889278).

Acts unidirectionally by moving in the 5' to 3' direction along the bound single-stranded DNA (PubMed:9889278).

Phosphorylation-dependent sequence-specific endoribonuclease in vitro (PubMed:11604510).

Cleaves exclusively between cytosine and adenine and cleaves MYC mRNA preferentially at the 3'-UTR (PubMed:11604510).

Biological Process

Defense response to virus Source: UniProtKB
Innate immune response Source: UniProtKB-KW
Negative regulation of canonical Wnt signaling pathway Source: Ensembl
Positive regulation of stress granule assembly Source: UniProtKB
Positive regulation of type I interferon production Source: UniProtKB
Ras protein signal transduction Source: ProtInc
Stress granule assembly Source: UniProtKB

Cellular Location

Cytosol; Nucleus; Perikaryon; Stress granule. Cytoplasmic in proliferating cells (PubMed:11604510). Cytosolic and partially nuclear in resting cells (PubMed:11604510). Recruited to stress granules in response to arsenite treatment (PubMed:12642610, PubMed:20180778). The unphosphorylated form is recruited to stress granules (PubMed:12642610). HRAS signaling contributes to this process by regulating G3BP dephosphorylation (PubMed:12642610).

PTM

(Microbial infection) Cleaved by human enterovirus 71; this cleavage induces the disassembly of cytoplasmic stress granules (PubMed:30006004). Cleaved by Foot-and-mouth disease virus; this cleavage suppresses the formation of cytoplasmic stress granules (PubMed:30404792).
Phosphorylated exclusively on serine residues. Hyperphosphorylated in quiescent fibroblasts. Hypophosphorylation leads to a decrease in endoribonuclease activity (By similarity). RASA1-dependent phosphorylation of Ser-149 induces a conformational change that prevents self-association. Dephosphorylation after HRAS activation is required for stress granule assembly. Ser-149 phosphorylation induces partial nuclear localization.
Arg-435 is dimethylated, probably to asymmetric dimethylarginine.