RBM9 Full-Length MS Protein Standard (NP_001026865), Labeled with [U- 13C6, 15N4]-L-Arginine and [U- 13C6, 15N2]-L-Lysine, was produced in human 293 cells (HEK293) with fully chemically defined cell culture medium to obtain incorporation efficiency at Creative-Proteomics. This gene is one of several human genes similar to the C. elegans gene Fox-1. This gene encodes an RNA binding protein that is thought to be a key regulator of alternative exon splicing in the nervous system and other cell types. The protein binds to a conserved UGCAUG element found downstream of many alternatively spliced exons and promotes inclusion of the alternative exon in mature transcripts. The protein also interacts with the estrogen receptor 1 transcription factor and regulates estrogen receptor 1 transcriptional activity. Multiple transcript variants encoding different isoforms have been found for this gene.