This entry represents the RNA recognition motif 1 (RRM1) of SRSF1 (also knwon as ASF/SF2). SRSF1 is a member of the SR (serine/arginine) protein family of splicing regulators. Besides mRNA splicing, it is also involved in regulating mRNA transcription, stability and nuclear export, NMD, and translation, as well as protein sumoylation. It has been identified as a proto-oncogene. SRSF1 contains two RRMs, which are required for efficient RNA binding and splicing []. The SR protein family is a group of mRNA metabolism regulators. Its members have a modular domain with one or two RNA-recognition motifs (RRMs) and a C-terminal RS domain comprising multiple Arg-Ser dipeptide repeats. There are 12 human SR proteins [].
Nuclear speckles are subnuclear storage sites containing pre-mRNA splicing machinery. Nuclear speckle splicing regulatory protein 1 (Nsrp1), also known as NSRP70, is a nuclear speckle-related protein that mediates alternative splice site selection, targeting several pre-mRNAs []. It contains an N-terminal coiled-coil domain that is critical not only for self-oligomerization but also for splicing activity. It interacts physically with two SR (serine/arginine) proteins, SRSF1 and SRSF2, and reverses their splicing activity in terms of CD44 exon v5 as exon exclusion [].
