Herpes simplex virus enhances chemokine function through modulation of receptor trafficking and oligomerization

Glycoprotein G (gG) from herpes simplex virus 1 and 2 (HSV-1 and HSV-2, important human neurotropic pathogens) is the first viral chemokine-binding protein found to potentiate chemokine function. Here we show that gG attaches to cell surface glycosaminoglycans and induces lipid raft clustering, increasing the incorporation of CXCR4 receptors into these microdomains. gG induces conformational rearrangements in CXCR4 homodimers and changes their intracellular partners, leading to sustained, functional chemokine/receptor complexes at the surface. This results in increased chemotaxis dependent on the cholesterol content of the plasma membrane and receptor association to Src-kinases and phosphatidylinositol-3-kinase signalling pathways, but independent of clathrin-mediated endocytosis. Furthermore, using electron microscopy, we show that such enhanced functionality is associated with the accumulation of low-order CXCR4 nanoclusters. Our results provide insights into basic mechanisms of chemokine receptor function and into a viral strategy of immune modulation.This work was funded by the Spanish Ministry of Science and Innovation (SAF2009-07857 and SAF2012-38957) and Red Española de Esclerosis Múltiple (Instituto de Salud Carlos III, RD07/0060/0014). N.M.-M. was funded by a studentship from Consejo Superior de Investigaciones Científicas and by Fundación Severo Ochoa. A.V.-B. was supported by a postdoctoral fellowship from Consejo Superior de Investigaciones Científicas.Peer Reviewe