Based on limited published evidence, DENND4B is a guanine nucleotide exchange factor (GEF) that activates RAB10 by promoting GDP-to-GTP exchange on Rab proteins, regulating their signal transduction 1. It localizes to the Golgi apparatus, cytoplasmic vesicles, and cytosol. A genome-wide CRISPR activation screen identified DENND4B as a top hit for increasing type VII collagen expression in keratinocytes, suggesting potential involvement in collagen regulation 1. DENND4B variants have been detected in pancreatic stellate cell samples, though functional characterization remains limited 2.