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Drebrin restricts rotavirus entry by inhibiting dynamin-mediated endocytosis
Bin Li1,2,3,4, Siyuan Ding5,2,3, Ningguo Feng1,2,3
1Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305.
Insights
Drebrin (DBN1) restricts rotavirus (RV) entry into host cells. Blocking DBN1 enhances RV infection and viral shedding, revealing its role in regulating dynamin-dependent endocytosis.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Rotavirus (RV) causes severe diarrhea in children globally, despite available vaccines.
- RV entry into host cells is mediated by the outer capsid protein VP4.
- Understanding RV-host interactions is crucial for developing new interventions.
Purpose of the Study:
- To identify host proteins interacting with RV VP4.
- To elucidate the role of identified proteins in RV entry.
- To investigate drebrin's function in viral infections and endocytosis.
Main Methods:
- Tandem affinity purification coupled with mass spectrometry to identify VP4 interacting proteins.
- siRNA silencing, CRISPR knockout, and chemical inhibition to study DBN1 function.
- Analysis of RV infection in DBN1 knockout mice and DBN1-deficient cells.
- Assays for uptake of other dynamin-dependent cargos.
Main Results:
- Drebrin (DBN1), an actin-binding protein, was identified as a VP4 interactor.
- Blocking DBN1 function increased host cell susceptibility to RV infection.
- Dbn1 knockout mice showed increased diarrhea and viral shedding.
- DBN1 deficiency enhanced the uptake of other dynamin-dependent cargos, including viruses.
- DBN1 suppresses dynamin-mediated endocytosis via cortactin interaction.
Conclusions:
- DBN1 plays a critical role in restricting rotavirus entry.
- DBN1 acts as a negative regulator of dynamin-dependent endocytosis for various cargos, including viruses.
- This finding offers new insights into viral entry mechanisms and potential therapeutic targets.
Abstract:
Despite the wide administration of several effective vaccines, rotavirus (RV) remains the single most important etiological agent of severe diarrhea in infants and young children worldwide, with an annual mortality of over 200,000 people. RV attachment and internalization into target cells is mediated by its outer capsid protein VP4. To better understand the molecular details of RV entry, we performed tandem affinity purification coupled with high-resolution mass spectrometry to map the host proteins that interact with VP4. We identified an actin-binding protein, drebrin (DBN1), that coprecipitates and colocalizes with VP4 during RV infection. Importantly, blocking DBN1 function by siRNA silencing, CRISPR knockout (KO), or chemical inhibition significantly increased host cell susceptibility to RV infection. Dbn1 KO mice exhibited higher incidence of diarrhea and more viral antigen shedding in their stool samples compared with the wild-type littermates. In addition, we found that uptake of other dynamin-dependent cargos, including transferrin, cholera toxin, and multiple viruses, was also enhanced in DBN1-deficient cells. Inhibition of cortactin or dynamin-2 abrogated the increased virus entry observed in DBN1-deficient cells, suggesting that DBN1 suppresses dynamin-mediated endocytosis via interaction with cortactin. Our study unveiled an unexpected role of DBN1 in restricting the entry of RV and other viruses into host cells and more broadly to function as a crucial negative regulator of diverse dynamin-dependent endocytic pathways.