Splicing Regulatory Small Protein (SRSP)

The PPP3CA divergent transcript, most accurately named Splicing Regulatory Small Protein (SRSP), is the product of an lncRNA (LOC90024, also called PPP3CA-DT in some systems). SRSP is a 130-amino acid microprotein that regulates pre-mRNA splicing, interacting with splicing regulators (particularly SRSF3) to promote inclusion of specific exons in target genes (notably the transcription factor Sp4). Upregulation of SRSP in cancer cells drives splicing isoforms that enhance tumorigenesis, especially in colorectal cancer, and high expression has been proposed as a poor-prognosis biomarker for this disease. SRSP is mechanistically distinct from the protein phosphatase family PPP3CA (calcineurin A alpha): the term "divergent transcript" simply refers to its genomic location, not functional homology. There are currently no therapeutics directly targeting SRSP, but its activity highlights the role of lncRNA-encoded microproteins as new classes of therapeutic targets and biomarkers.

Other names

PPP3CA divergent transcriptPPP3CA-DTFLJ20021FLJSRSPSplicing Regulatory Small Protein

Drugs (if developed) would likely inhibit protein-protein interaction, RNA/protein expression, or splicing modulation