Different HIV-1 gp120 envelope protein mutants differentially affect calcium responses in cultured cortical astrocytes

The HIV-1 envelope glycoprotein gp120 is involved in HIV-1 cell entry. It is released from infected cells within the brain and plays a crucial role in the pathogenesis of HIV- encephalopathy. Depending on its sequence, gp120 binds to alpha (CXCR4)- or beta (CCR5)- chemokine receptors, which are present on neurons, astrocytes and microglial cells. Activation of chemokine-receptors resulted in calcium increase due to calcium release from internal stores. In cultured cortical astrocytes, incubation with gp120 led to a significant reduction of calcium transients elicited by physiological stimuli (Köller et al., J. N…