of GTPase. As well, experimental evidence suggests that the DEP domain determines the subcellular target of some GTPase Activating proteins. In the DEPDC1B protein electronic inference has verified the GTPase activator activity function. The solution structure of human containing DEP domain containing proteins verifies the secondary structure of the domain: containing three alpha-helices and two beta-strands within the approximate 80 amino acid region of the domain. The RhoGAP domain is another structural domain known to interact with GTPase and small GTPase. Research concerning the domain in other proteins indicates an approximately similar function among the domain in various proteins. The domain has been verified to interact with other proteins to form complexes or interact with other structures of the cell such as the cytoskeleton or plasma membrane. Post-translational modification DEPDC1B protein product is predicted to be highly phosphorylated after translation. A single sumoylation site, found within the RhoGAP domain, indicates the possible interaction of the protein with a SUMO protein, enabling or inhibiting interaction with other proteins. A single palmitoylation site, found within the RhoGAP domain, indicates the possible interaction of the DEPDC1B protein product with a membrane via lipid anchor. No conserved glycolation sites are predicted within the mature DEPDC1B protein product. No signal peptide or transmembrane domains are predicted within human or any ortholog protein. No prenylation sites are predicted in any DEPDC1B orthologs. Expression Expression of DEPDC1B is reported to be largely ubiquitous throughout mouse tissue. High level of gene expression is observed in all periods of life, except early zygote stages. Experimental evidence suggests that DEPDC1B presents similar ubiquitous expression in all tissues. Differential expression profiles suggest that DEPDC1B is higher expressed in many cancerous disease states, including: papillary thyroid cancer, breast cancer, synovial sarcoma, and prostatic cancer progression. Also, DEPDC1B expression decreases in environments of beta-catenin depletion in multiple myeloma cell lines Interactions No interactions of DEPDC1B within any other protein product characterized by experimentation have been verified. Medium coexpression of DEPDC1B with ECT2 in cell cycle regulation and DNA synthesis was verified by similarity of expression in various tissues. The remaining predicted interaction were determined via datamining. Homology Orthologs DEPDC1B is unique to Chordates in Kingdom Animalia Multiple sequence alignments verify that DEPDC1B is highly conserved among orthologs. The two structural domains (DEP and RhoGAP) are the two most conserved elements of the proteins. Various motifs are also conserved throughout the protein. No data