Biosensors to study membrane curvature stabilization during HPV16 endocytosis
Viruses are obligatory intracellular parasites that hijack cellular mechanisms for host cell entry and replication. Therefore, they are valuable tools to study fundamental cell biological mechanisms. Our previous studies on human papillomavirus type 16 (HPV16) endocytosis led to the identification of a novel endocytic mechanism with unknown cellular function. Virus uptake occurs via inward budding vesicles devoid of a visible coat that undergo fission in an actin dependent manner. The absence of a visible coat prompted us to investigate whether curvature sensing BAR domain proteins stabilize membrane curvatures during HPV16 endocytosis. We identified the BAR domain proteins sorting nexin 2 (SNX2) and ArfGAP with SH3 domain, ankyrin repeat and PH domain 1 (ASAP1) as mediators of virus uptake.
Here, we propose to identify new curvature biosensors to assess, which steps of membrane curvature formation require the action of SNX2 and ASAP1 (Aim 1). Moreover, we will study which curvatures are generated at base and neck of HPV16 endocytic vesicles with help of existing biosensors (Aim 2). Answering these questions will contribute to a more detailed understanding of the novel endocytic pathway for HPV16 uptake.