Nucleolin, RNA recognition motif 4 (IPR034235)

Short name: Nucleolin_RRM4

Overlapping homologous superfamilies

Domain relationships


This entry represents the RNA recognition motif 4 (RRM4) of ubiquitously expressed protein nucleolin.

Nucleolin is a multifunctional major nucleolar phosphoprotein that has been implicated in various metabolic processes, such as ribosome biogenesis, cytokinesis, nucleogenesis, cell proliferation and growth, cytoplasmic-nucleolar transport of ribosomal components, transcriptional repression, replication, signal transduction, inducing chromatin decondensation, etc [PMID: 10036227, PMID: 17484127]. Nucleolin exhibits intrinsic self-cleaving, DNA helicase, RNA helicase and DNA-dependent ATPase activities [PMID: 9918513]. It can be phosphorylated by many protein kinases, such as the major mitotic kinase Cdc2, casein kinase 2 (CK2), and protein kinase C-zeta [PMID: 9918513, PMID: 9388266].

Nucleolin shares similar domain architecture with gar2 from Schizosaccharomyces pombe [PMID: 9211981] and NSR1 from Saccharomyces cerevisiae. The highly phosphorylated N-terminal domain of nucleolin is made up of highly acidic regions separated from each other by basic sequences, and contains multiple phosphorylation sites. The central domain of nucleolin contains four closely adjacent N-terminal RNA recognition motifs (RRMs), which suggests that nucleolin is potentially able to interact with multiple RNA targets. The C-terminal RGG (or GAR) domain of nucleolin is rich in glycine, arginine and phenylalanine residues, and contains high levels of NG, NG-dimethylarginines. RRM1, together with RRM2, binds specifically to RNA stem-loops containing the sequence (U/G)CCCG(A/G) in the loop [PMID: 17157503].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.