This domain found at the C-terminal of Nuclear speckle splicing regulatory protein 1 (NRP1, also known as Nuclear speckle-related protein 70 and Coiled-coil domain-containing protein 55). This is the RS-like domain, that resembles the arginine/serine-rich (RS) domain in other SR proteins, interacts with two SR proteins and with target mRNA, being essential for NRP1 activity. NRP1 is a RNA-binding protein that mediates pre-mRNA alternative splicing regulation [1,2].

1: Nuclear Speckle-related Protein 70 Binds to Serine/Arginine-rich Splicing Factors 1 and 2 via an Arginine/Serine-like Region and Counteracts Their Alternative Splicing Activity. Kim CH, Kim YD, Choi EK, Kim HR, Na BR, Im SH, Jun CD; J Biol Chem. 2016;291:6169-6181. PMID:26797131

2: NSrp70 is a novel nuclear speckle-related protein that modulates alternative pre-mRNA splicing in vivo. Kim YD, Lee JY, Oh KM, Araki M, Araki K, Yamamura K, Jun CD; Nucleic Acids Res. 2011;39:4300-4314. PMID:21296756