The HIV-1 coat protein gp120 regulates CXCR4-mediated signaling in neural progenitor cells.

We demonstrate that hCD4-primed gp120IIIB interacts with CXCR4 receptors expressed by postnatal mouse neural progenitor cells and elicits robust Ca(2+) signals. The chemokine SDF-1 acted as a chemoattractant and a mitogenic stimulus for these neural progenitor cells. Although hCD4/gp120 was not able to produce chemoattraction or increase proliferation, it completely blocked the ability of SDF-1 to produce these effects. Thus, gp120 can act both as an agonist and de facto antagonist of CXCR4-mediated signaling in neural progenitor cells. It is possible that the ability of hCD4/gp120 to block SDF-1 signaling in neural progenitors may contribute to the neuropathological effects of HIV-1.