The ARF-GEP(100) Sec7 domain contains Asp(543) and Met(555), corresponding to residues associated with sensitivity to the inhibitory effect of the fungal metabolite brefeldin A (BFA) in yeast Sec7, but also Phe(535) and Ala(536), associated with BFA-insensitivity.     ///    "No similar coincidence of ARF-GEP(100) with AP-1, AP-2, catenin, LAMP-1, or 58K was observed. "    ///    "ARF-GEP(100), a guanine nucleotide-exchange protein for ADP-ribosylation factor 6.. "    ///    The coarse punctate distribution of EEA-1 in regions nearer the nucleus appeared to coincide with that of ARF-GEP(100) in those areas.     ///    "Consistent with its structure, ARF-GEP(100) activity was not affected by BFA or phospholipids. "    ///    "ARF-GEP(100) accelerated [(35)S]GTPgammaS binding to ARF1 (class I) and ARF5 (class II) 2- to 3-fold, and to ARF6 (class III) ca. "    ///    "On Northern blot analysis of human tissues, a approximately 8-kb mRNA that hybridized with an ARF-GEP(100) cDNA was abundant in peripheral blood leukocytes, brain, and spleen. "    ///    "After subcellular fractionation of cultured T98G human glioblastoma cells, ARF6 was almost entirely in the crude membrane fraction, whereas ARF-GEP(100), a 100-kDa protein detected with antipeptide antibodies, was cytosolic. "