Caper, also known as splicing factor HCC1 or hepatocellular carcinoma protein 1 and RNA binding region containing protein 2 (RNPC2), acts as a transcriptional coactivator for steroid nuclear receptors c-Jun, ERalpha and ER-beta. Caper, a nuclear protein with highest concentrations in nuclear speckles, plays a role in the pre-mRNA splicing process. Two isoforms of Caper, HCC1.3 and HCC1.4, co-localize with pre-mRNA splicing factor SC35 and uridine-rich small nuclear RNAs. Caper is a widely expressed protein with highest levels detected in skeletal muscle, lung, brain and pancreas.
