arginineserinerich

Arginineserinerich refers to protein regions that are unusually enriched in the amino acids arginine (R) and serine (S). In molecular biology, the term is most commonly used for RS-rich domains found in a family of splicing factors known as SR proteins. These domains typically consist of repeats of the dipeptides RS or SR and can extend over several tens to more than a hundred amino acids.

RS domains are a hallmark of SR proteins such as SRSF1 and related factors. They mediate protein–protein interactions with other components of the spliceosome and with other splicing regulators, facilitating the assembly and regulation of the splicing machinery on nascent pre-mRNA transcripts. The arginine-rich portion contributes to electrostatic interactions, while the serine-rich portion provides sites for post-translational modification.

A central aspect of arginineserinerich regions is their regulation by phosphorylation. Serine residues within RS domains are substrates for serine/arginine-rich protein kinases (SRPKs) and CLK kinases, among others. Phosphorylation alters the interaction network, subcellular localization, and activity of SR proteins, influencing splice site selection and the balance between constitutive and alternative splicing.

Biological significance of arginineserinerich regions lies in their essential role for proper pre-mRNA processing. Dysregulation of RS-domain phosphorylation or SR protein function has been linked to diseases such as cancer and neurodegenerative disorders, highlighting their importance in gene expression control. The presence and pattern of RS repeats can vary across species and proteins, reflecting evolutionary adaptation of splicing regulation.