RAPGEF6 is a guanine nucleotide exchange factor (GEF) that activates Rap1A, Rap2A, and M-Ras small GTPases 1 and does not interact with cAMP 2. In mechanotransduction, RAPGEF6 (also known as PDZGEF2) is activated by phosphatidic acid downstream of phospholipase Cγ1 signaling in response to low extracellular matrix stiffness, subsequently activating RAP2 to regulate the Hippo pathway effectors YAP and TAZ 1. RAPGEF6 plays critical roles in neurological function; Rapgef6 deletion in mice impairs amygdala-dependent fear conditioning and reduces hippocampal spine density, suggesting relevance to schizophrenia pathophysiology 3. In sepsis, RAPGEF6 emerges as a temporally dynamic biomarker with high diagnostic accuracy (AUROC 0.92), correlating strongly with M1 macrophage infiltration; RAPGEF6 knockdown attenuates LPS-induced inflammation and oxidative stress via NF-κB-mediated necroptosis inhibition 4. In cancer biology, RAPGEF6 expression associates with poor survival outcomes in HER2-positive breast cancer 5 and gastric cancer through alternative splicing regulation by NOVA2 6. Additionally, a novel ETV6::RAPGEF6 fusion gene has been identified in chr5 eosinophilic leukemia with IL3 overexpression 7. These diverse functions position RAPGEF6 as a multifunctional signaling hub with therapeutic implications across neuropsychiatric, inflammatory, and malignant diseases.