HPV16 Induces Formation of Virus-p62-PML Hybrid Bodies to Enable Infection

Abstract

Human papillomaviruses (HPVs) inflict a significant burden on the human population. The clinical manifestations caused by high-risk HPV types are cancers at anogenital sites, including cervical cancer, as well as head and neck cancers. Host cell defense mechanisms such as autophagy are initiated upon HPV entry. At the same time, the virus modulates cellular antiviral processes and structures such as promyelocytic leukemia nuclear bodies (PML NBs) to enable infection. Here, we uncover the autophagy adaptor p62, also known as p62/sequestosome-1, as a novel proviral factor in infections by the high-risk HPV type 16 (HPV16). Proteomics, imaging and interaction studies of HPV16 pseudovirus-treated HeLa cells display that p62 is recruited to virus-filled endosomes, interacts with incoming capsids, and accompanies the virus to PML NBs, the sites of viral transcription and replication. Cellular depletion of p62 significantly decreased the delivery of HPV16 viral DNA to PML NBs and HPV16 infection rate. Moreover, the absence of p62 leads to an increase in the targeting of viral components to autophagic structures and enhanced degradation of the viral capsid protein L2. The proviral role of p62 and formation of virus-p62-PML hybrid bodies have also been observed in human primary keratinocytes, the HPV target cells. Together, these findings suggest the previously unrecognized virus-induced formation of p62-PML hybrid bodies as a viral mechanism to subvert the cellular antiviral defense, thus enabling viral gene expression.

Human papillomavirus associated cervical lesion: pathogenesis and therapeutic interventions

“…The GTPase‐activating protein folliculin safeguards incoming HPV virions from lysosomal degradation, 41 similar to the role of coat protein complex I 42 . The virus remains within in the Golgi until cell cycle progression into mitosis, when the breakdown of the nuclear membrane facilitates the accumulation of viral DNA at promyelocytic leukemia nuclear bodies, where is the site of viral transcription and replication 31,37,43 . However, the process of intranuclear delivery and the cellular proteins involved in these steps remain uncertain.…”

“…Rizzato's study demonstrated that the CDK1 and PLK1 sequentially phosphorylate the chromosome binding region of L2 to regulate the delivery of HPV viral DNA to mitotic chromatin during mitosis 44 . Additionally, the autophagy adaptor p62 may also have involvement in the nuclear delivery process 43 . Numerous studies have investigated the mechanism of HPV entry.…”

“… 42 The virus remains within in the Golgi until cell cycle progression into mitosis, when the breakdown of the nuclear membrane facilitates the accumulation of viral DNA at promyelocytic leukemia nuclear bodies, where is the site of viral transcription and replication. 31 , 37 , 43 However, the process of intranuclear delivery and the cellular proteins involved in these steps remain uncertain. Several proteins, such as Ran‐binding protein 10, karyopherin alpha, and dynein light chain DYNLT3, can bind to L2 and assist in its transport toward mitotic chromatin.…”

The interactions between PML nuclear bodies and small and medium size DNA viruses

“…Furthermore, Daxx downregulation negatively affected the expression of early genes and, consequently, viral genome replication. Finally, Schweiger et al [ 149 ] recently showed that the autophagy receptor p62 binds to subviral particles in endosomes and accompanies them to the nucleus, where hybrid p62-subviral particle-PML assemblies are detected. The authors suggested that the interaction between subviral particles and p62 exerts a protective effect on the viral genome.…”

“…The authors suggested that the interaction between subviral particles and p62 exerts a protective effect on the viral genome. p62 depletion resulted in the degradation of L2 and a decrease in the expression of the reporter gene carried by the pseudovirions [ 149 ].…”