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During entry, human papillomavirus (HPV) traffics from the endosome to the trans Golgi network (TGN) and Golgi and then the nucleus to cause infection. Although dynein is thought to play a role in HPV infection, how this host motor recruits the virus to support infection and which entry step(s) requires dynein are unclear. Here we show that the dynein cargo adaptor BICD2 binds to the HPV L2 capsid protein during entry, recruiting HPV to dynein for transport of the virus along the endosome-TGN/Golgi axis to promote infection. In the absence of BICD2 function, HPV accumulates in the endosome and TGN and infection is inhibited. Cell-based and in vitro binding studies identified a short segment near the C-terminus of L2 that can directly interact with BICD2. Our results reveal the molecular basis by which the dynein motor captures HPV to promote infection and identify this virus as a novel cargo of the BICD2 dynein adaptor.
Strengths
The BICD2-L2 interaction is supported by immunoprecipitation-mass spectrometry, co-IP time courses, proximity ligation in intact cells, direct binding of purified proteins, and knockdown-rescue, providing strong triangulation across independent methods.
↳ Results, Figs 1-4
A dynein-binding-defective A/V BICD2 mutant fails to rescue infection while retaining cargo binding, and siRNA-resistant rescue constructs confirm on-target specificity, isolating the dynein-coupling function from off-target effects.
↳ Results, Fig 4A-C
BICD2 is required for HPV5, HPV16, and HPV18 infection, and the L2 C-terminal binding region is conserved across these types, indicating the recruitment mechanism is broadly applicable.
↳ Results, Fig 3C-D and S3A Fig
Limitations
Key claims about motor-driven transport rest on co-IP and proximity ligation signals together with depletion phenotypes rather than direct visualization of dynein-driven movement of the virus.
↳ Results, Figs 1, 4, 5
The BICD2 binding segment overlaps the retromer binding site and the cell-penetrating peptide, and alanine substitutions disrupt all functions together, so the trafficking defect cannot be cleanly attributed to loss of BICD2 binding alone.
↳ Results, Fig 2; Discussion, paragraph 5
Experiments use HeLa and HaCaT cells and pseudovirus systems, with no validation in primary keratinocytes, the natural HPV target tissue, or in vivo, limiting physiological generalizability.
↳ Materials and Methods; Results
The scores reflect a coherent, well-controlled mechanistic study whose central advance is identifying BICD2 as the dynein adaptor for HPV and localizing the interaction to a defined L2 segment. Evaluation converged on the strength of the multi-assay triangulation and the dynein-binding-defective mutant control, which together make the BICD2-L2-dynein link convincing. The principal point of divergence concerned execution: the binding site mapped in Fig 2 overlaps the retromer site and cell-penetrating peptide, and because no separation-of-function L2 mutant exists, the trafficking defect cannot be attributed solely to BICD2 binding, which bounds both Methodological Rigour and Contribution below the top band. Impact potential is decoupled from quality and sits in the recognized-problem-area range because the findings are pre-translational, conducted in transformed cell lines without a therapeutic prototype.
Strong4.0/5.0
The paper identifies BICD2 as the cargo adaptor bridging HPV L2 to dynein and maps the interaction to a 20-amino-acid L2 C-terminal segment, filling a defined mechanistic gap in HPV entry and adding a novel cargo to the BICD2 field. The contribution is bounded by the inability to generate separation-of-function L2 mutants that ablate BICD2 binding without disrupting other L2 functions.
we cannot rigorously test the model that BICD2 binding to L2 is required for proper trafficking
Execution is strong through orthogonal assays (IP-MS, co-IP time courses, PLA, purified-protein binding, KD-rescue) and well-chosen controls including the dynein-binding-defective A/V BICD2 mutant. The score is bounded because central inferences rest on co-IP/PLA proximity and depletion rather than direct transport measurement, and the mapped binding site overlaps the retromer site and CPP, preventing clean functional separation.
Substitution of either the retromer binding site or the CPP with alanines... severely impaired BICD2 binding
The argument proceeds logically from interaction discovery to direct binding to functional KD-rescue and trafficking consequences, with a summarizing model figure. Minor imprecision arises where the discussion moves from association to 'recruits' and 'coupling' beyond what proximity and depletion strictly demonstrate.
recruiting HPV to dynein for transport of the virus along the endosome-TGN/Golgi axis
The paper engages substantively with prior HPV entry literature (retromer, Rab, COPI, dynein light chain) and BICD2 biology, positioning itself as filling a specific mechanistic gap and honestly noting unresolved questions such as the role of BICDR1. Comparison to the yeast two-hybrid L2-dynein study and to RanBP10/KPNA2 contextualizes the finding.
different dynein adaptors may act at different stages during HPV entry
Lower confidence on Methodological Rigour — domain match limited.
Watch-outs4 of 4 checks
The paper is internally consistent across abstract, results, and discussion, with converging evidence (IP-MS, co-IP time courses, PLA, in vitro binding, KD-rescue) and no numerical contradictions or methods-results mismatches. Mechanistic language such as 'recruits' and 'coupling' is somewhat strong relative to proximity and depletion data, but claims remain directionally aligned with the evidence and the authors explicitly caveat the absence of separation-of-function mutants.
No image integrity, COI, or protocol-registration red flags were identified. Ethics approval is not stated (acceptable for established cell lines but undeclared) and no data or code availability statement is provided.
Flags: 0 declared / 5 total
All 52 cited references resolved to real publications via PubMed, Crossref, or OpenAlex.
No retraction notice found in Retraction Watch.
Sources: Retraction Watch ✓PubPeer (coming soon)
Medium3.1/5.0
The work connects to a recognized applied problem, the absence of antivirals against established HPV infection, and nominates BICD2 and the L2 binding segment as candidate targets. No specific near-term decision-maker or drug program is named, keeping traction mid-range.
there are currently no antiviral treatments to target established HPV infections
Findings sit at the mechanism-characterized proof-of-concept stage in cultured cells with no intervention, assay, or therapeutic prototype derived from the work. This pre-translational status places the component in the lower-middle range.
we cannot rigorously test the model
BICD2 dependence is shown across HPV5, HPV16, and HPV18 with a conserved L2 C-terminal binding region and two cell lines, supporting moderate cross-type breadth. All work remains in transformed cultured cells and pseudovirus systems without in vivo or primary keratinocyte validation.
The C-terminus of HPV5 and HPV18 L2 corresponding to HPV16 L2 434-461 are conserved
The study resolves a specific missing link, how dynein is recruited to the HPV cargo, and supplies a concrete 20-amino-acid peptide as a foundation for follow-on mechanistic and therapeutic work. It advances a cumulative pathway without itself establishing a validated target class.
a novel cargo for the BICD2 dynein adaptor during the early stages of HPV trafficking
Nabu’s assessment, alongside the field’s view.
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