Novel trafficking pathway controling HPV infection

• Applicant: Professorin Dr. Luise Florin
• Subject Area: Virology ; Cell Biology
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280365264

In all eukaryotic cells, the endocytic apparatus manages the careful sorting of cargoes and the intracellular delivery of plasma membrane receptors and their ligands such as viruses. We were able to show that human papillomavirus type 16 (HPV16) uses a novel Clathrin-, caveolin- and dynamin-independent endocytosis for infection of human cells. We showed that virus internalization is mediated via tetraspanin-enriched microdomains in association with the tetraspanins CD151 and CD63, which results in virus accumulation in tetraspanin CD63 positive vesicles. Intracellular trafficking of incoming HPV viruses resulting in capsid disassembly and uncoating of the viral DNA is still poorly understood. We observed colocalisation of CD63 and HPV on the plasmamembrane and in intracellular vesicles, which leads to recruitment of the CD63-interaction partner syntenin-1. The CD63/syntenin-1 complex regulates various aspects of trafficking. Therefore, these cellular proteins are attractive candidates that might regulate the so far uncharacterized pathway of papillomavirus entry. The research program will focus on the following aims:1. To define the role of CD63 and syntenin-1 in HPV16 intracellular trafficking (live-microscopy to follow the dynamics of HPV16 trafficking through endocytic compartments)2. To investigate interaction of syntenin-1 and CD63 in relation to HPV16 infection (expression recovery experiments using various CD63-/syntenin-1 mutants to map critical regions required for HPV infection). 3. We will examine the significance of syntenin-1 phosphorylation in HPV infection. Here, syntenin-1 phos-Y4- and phos-S6-specific antibodies, phosphorylation-deficient syntenin-1 mutants and kinase-siRNAs or -inhibitors will be tested.4. To examine CD63 and syntenin-1 peptides on their potential to block infectivity by different papillomaviruses.This study will contribute to a more in depth understanding of the early endosomal trafficking pathway that controls HPV entry and infection by building upon novel data that link the tetraspanin CD63 and its adaptor protein syntenin-1 to HPV infection. Thus, detailed understanding of this pathway may provide a solid basis for developing novel therapeutic antiviral strategies.

• DFG Programme: Research Grants