RGL2 is a guanine nucleotide exchange factor (GEF) that functions as a downstream effector of Ras and Rap1 signaling 1. It catalyzes nucleotide exchange on the small GTPase RalA, promoting GTP loading and RalA/RalB activation 2. RGL2 localizes to endomembranes including early endosomes, recycling endosomes, and autophagosomes, where it activates RalB to coordinate cellular responses 3. Structurally, RGL2 contains a Ras-binding domain that forms a distinct 2:2 heterotetrameric complex with oncogenic KRas, differing from canonical Ras:effector interactions 4. PKA phosphorylation of RGL2's C-terminal Ras-binding domain reduces H-Ras binding capacity, providing a regulatory mechanism 2. Clinically, RGL2 overexpression promotes pancreatic cancer growth through both Ral-dependent and Ral-independent mechanisms 5. In the heart, RGL2 upregulation protects cardiomyocytes from stress-induced death and fibrosis by activating PI3-kinase signaling downstream of RalB activation 6. Conversely, RGL2 deficiency impairs erythroid differentiation by altering terminal differentiation and apoptosis pathways 7. These findings identify RGL2 as a multifunctional signaling hub with therapeutic potential in cancer and heart disease contexts.