RGGcontaining

RGG-containing refers to proteins that contain one or more RGG repeats — tripeptides of arginine-glycine-glycine. These motifs, often embedded in low-complexity regions, are enriched in a class of RNA-binding proteins and are frequently referred to as GAR (glycine-arginine-rich) domains.

Structurally, RGG repeats are flexible and may be interspersed with other residues; they are common in nuclear and nucleolar proteins across eukaryotes. They contribute to phase separation and the formation of ribonucleoprotein granules.

Functionally, RGG motifs mediate RNA binding, including interactions with structured RNA elements such as G-quadruplexes, and facilitate processes like splicing, transport, localization, and translation regulation. They also promote protein-protein interactions within RNP complexes.

Post-translational modification: Arginine residues within RGG repeats are targets of protein arginine methyltransferases, producing symmetric or asymmetric dimethylarginine. Methylation modulates RNA affinity, interaction networks, and phase separation, influencing stress responses and granule dynamics.

Examples and relevance: Notable RGG-containing proteins include FMRP, nucleolin, and several heterogeneous nuclear ribonucleoproteins; members of the FET family such as FUS, EWSR1, and TAF15 also contain RGG domains. RGG-containing proteins are implicated in human disease; expansions or mutations can contribute to Fragile X syndrome, amyotrophic lateral sclerosis, and cancer, though roles are diverse and context-dependent. RGG-containing proteins remain a focus of study for understanding RNA biology and cellular organization.