RNA recognition motif 3 (RRM3) found in epithelial splicing regulatory protein ESRP1, ESRP2, Drosophila RNA-binding protein Fusilli and similar proteins
This subfamily corresponds to the RRM3 of ESRPs and Fusilli. ESRP1 (also termed RBM35A) and ESRP2 (also termed RBM35B) are epithelial-specific RNA binding proteins that promote splicing of the epithelial variant of the fibroblast growth factor receptor 2 (FGFR2), ENAH (also termed hMena), CD44 and CTNND1 (also termed p120-Catenin) transcripts. They are highly conserved paralogs and specifically bind to GU-rich binding site. ESRP1 and ESRP2 contain three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The family also includes Drosophila fusilli (fus) gene encoding RNA-binding protein Fusilli. Loss of fusilli activity causes lethality during embryogenesis in flies. Drosophila Fusilli can regulate endogenous FGFR2 splicing and functions as a splicing factor. Fusilli shows high sequence homology to ESRPs and contains three RRMs as well. It also has an N-terminal domain with unknown function and a C-terminal domain particularly rich in alanine, glutamine, and serine.