ARFGEF1 (ARF guanine nucleotide exchange factor 1) is a critical regulator of intracellular vesicle trafficking that promotes guanine nucleotide exchange on ARF1 and ARF3, facilitating GDP-to-GTP replacement for protein activation. The protein plays essential roles in neuronal development and function, particularly in maintaining proper inhibitory neurotransmission. ARFGEF1 haploinsufficiency disrupts neuronal endosome composition and significantly decreases membrane surface postsynaptic GABA receptors, leading to impaired neuronal inhibition 1. Loss-of-function variants cause a neurodevelopmental disorder characterized by developmental delay, intellectual disability, behavioral abnormalities, and epilepsy with variable expressivity, transmitted in an autosomal dominant pattern 2. Functional validation studies demonstrate that ARFGEF1 mutations result in seizure-like behavior and decreased inhibitory interneurons in zebrafish models 3. Beyond its neurological roles, ARFGEF1 is involved in cancer progression, where it promotes cell migration and invasion through PI3K/Akt/NF-κB signaling pathways 4. The protein is regulated by transcription factors like KLF4 and microRNAs including miR-133b, which target ARFGEF1 to suppress tumor progression 5. These findings establish ARFGEF1 as a key player in both neurodevelopment and cellular trafficking processes.