DEP Domain Containing Protein 1B also known as XTP1, XTP8, HBV XAg-Transactivated Protein 8, [formerly referred to as BRCC3] is a human protein encoded by a gene of similar name located on chromosome 5. The precise function of DEPDC1B is currently unknown. Expression profiles indicate that DEPDC1B is highly expressed ubiquitously throughout human tissue. Gene structure Gene neighborhood DEPDC1B is found on the long arm of chromosome 5 (5q12.1), spanning 103kb on the minus strand. The gene neighborhood of DEPDC1B includes 5 other genes. Downstream are two genes SEPT21 and PDE4D. Upstream are another two genes ELOV7 and KRT8P31. On the complement strand is another gene in the same region PART1. Promoter DEPDC1B promoter region contains several transcription factors associated with proteins of ubiquitous expression. These transcription factors possess a central theme of cellular proliferation, cell cycle regulation, apoptosis, and differentiation. Few promoters unique to tumor suppression or tumorgenesis exist within the region as well. The following includes the top twenty Predicted Transcription Factors: mRNA structure Splice variants DEPDC1B possesses 13 mRNA splice variants that form two isoforms. Isoform 1 is the longest and is the most commonly used version of the gene. It is composed of 11 exons and is 103254bp in length. Isoform 2 is the second confirmed transcript variant. It is composed of 10 exons, missing the tenth exon of the first variant. The missing exon is 186bp in length. See Protein Structure section for more detail... Secondary structure DEPDC1B is predicted to be predominantly alpha-helical. No significant beta-strands or beta structures exist with the protein. . Stem loops and binding miRNA DEPDC1B is predicted to possess multiple stem loops in its 5' and 3' untranslated regions (UTR) . In the 3' UTR, miRNA has-miR-499-5p binds to a nucleotide region predicted as a stem loop. Protein structure Sequence The DEPDC1B gene possesses two novel proteoforms. The longest variation, coded by mRNA isoform 1, is the most commonly used. The protein is 529 amino acids in length. The second novel proteoform, DEPDC1B.2 is coded by 10 exons, missing the 10th exon from the longest variation. The protein is 467 amino acids in length. The missing 62 amino acids follow the RhoGAP domain, in a region predicted to be highly phosphorylated Domains DEPDC1B contains two structural domains: a DEP domain and a RhoGAP domain. The DEP domain is primarily found in proteins involved in G-protein signalling pathways and regulation