HIV-1 Nef co-localizes with the astrocyte-specific cytoskeleton protein GFAP in persistently nef-expressing human astrocytes

In T-cells HIV-1 Nef exerts various functions and interacts with actin. In astrocytes interaction of Nef with cellular proteins is poorly understood. Therefore, human astrocytic cell clones stably transfected with nef-genes derived from HIV-1 Bru and its myristoylation-defective TH-variant were investigated by confocal laser scanning microscopy for expression of Nef and cytoskeleton proteins actin and GFAP, a marker for activated astrocytes. Myristoylated Nef was detected in cytoplasm, Golgi and plasmamembrane, while non-myristoylated Nef was exclusively cytoplasmic. Nef co-localised with GFAP in the perinuclear region of astrocytes. In contrast, Nef did not interact with actin filaments in human astrocytes. Nef/GFAP interaction could contribute to changes in morphology and activation state of astrocytes shown previously which are both critical for development of astrogliosis in HIV-1 infected brain.