DIAPH1 (diaphanous related formin 1) is an actin nucleation and elongation factor that regulates F-actin assembly and cytoskeletal organization 1. Beyond its classical role in actin dynamics, DIAPH1 functions as a multifaceted signaling scaffold. It interacts with RAGE (receptor for advanced glycation end products) to regulate metabolic and inflammatory signaling, and couples with Rho signaling pathways to promote microtubule stabilization through APC localization 23. DIAPH1 also directly binds Mitofusin-2 to regulate mitochondria-ER contact sites, modulating oxidative stress and mitophagy—critical during ischemic stress 4. Disease relevance is substantial: DIAPH1 mutations cause sensorineural deafness and seizures with cortical blindness and microcephaly syndrome (SCBMS) 1. Loss-of-function mutations impair T cell proliferation, activation, and STAT5 signaling, alongside diminished NK cell cytotoxicity and reduced helper ILC populations, establishing DIAPH1's critical role in lymphocyte development and function 5. Elevated DIAPH1 in extracellular vesicles from HCV patients persists after viral clearance, suggesting involvement in hepatic fibrosis progression 6. The RAGE/DIAPH1 axis contributes to obesity, cardiometabolic dysfunction, atherosclerosis, and diabetic neuropathy 237. Recent work demonstrates AGER-DIAPH1 interaction mediates macropinocytosis-dependent chemotherapy resistance in pancreatic cancer 8.