YJU2B

Coiled-coil domain containing 130 is a protein that in humans is encoded by the CCDC130 gene. It is part of the U4/U5/U6 tri-snRNP in the U5 portion. This tri-snRNP comes together with other proteins to form complex B of the mature spliceosome. The mature protein is approximately 45 kilodaltons (kDa) and is extremely hydrophilic due to the abnormally high number of charged and polar amino acids. CCDC130 is a highly conserved protein, it has orthologous genes in some yeasts and plants that were found using nucleotide and protein versions of the basic local alignment search tool (BLAST) from the National Center for Biotechnology Information. GEO profiles for CCDC130 have shown that this protein is ubiquitously expressed, but the highest levels of expression are found in T-lymphocytes.

== Function == While the specific function of CCDC130 is still unknown, there have been several studies and research papers identifying it as a component of the U5 portion of the U4/U5/U6 tri-snRNP that helps form Complex B of the human spliceosome after coming together with Complex A. Complex B then undergoes more modifications and conformational changes before becoming a mature spliceosome. In one study, the conservation of spliceosomal components is discussed by comparing the human spliceosome with that of yeast. In this study, CCDC130 is categorized as a known splicing factor and its homolog in yeast is Yju2. This yeast protein is a splicing factor that helps form the complete, active spliceosome and promotes the first step of splicing, which involves cleavage at the 5' splice site of the first exon. Based on this information, it is likely that CCDC130 plays a similar role in the human spliceosome, but due to the higher complexity of the human spliceosome, this protein may perform other functions or a completely different function. Due to its high number of phosphorylation sites, it is likely that this protein is activated and recruited to the spliceosomal complex through phosphorylation or dephosphorylation (see Post-translational modifications). Since this gene is ubiquitously expressed and expressed 2.9 times higher than the average gene, it is clear that this protein plays an integral part in the proper function of the spliceosome.