Annexin A2 in Virus Infection.

Viral replication depends on host cell factors at multiple stages. While many host proteins are known to support viral life cycles, Annexin A2 (AnxA2) has emerged as a recurring participant in several infections. AnxA2 is a multifunctional protein found in various cellular compartments and can exist in monomeric or heterotetrameric forms. It interacts with S100A10 to form the AnxA2/S100A10 heterotetramer (A2t), which influences membrane dynamics and RNA regulation. Prior research has shown that AnxA2 supports endocytosis, exocytosis, and membrane organization—processes critical to viral entry and release. However, the role of AnxA2 in viral infections remains fragmented across the literature. No prior work had resolved the full scope of AnxA2's involvement in viral lifecycle stages. This gap motivated a synthesis of findings to identify patterns and inconsistencies. That uncertainty drove the need for a focused review of AnxA2's role in epithelial cell-targeting viruses.

The purpose of this mini review is to consolidate findings on AnxA2's involvement in viral infections that target epithelial cells. The authors aim to highlight recurring themes in AnxA2's function across different viruses. By compiling data from various studies, they seek to identify common mechanisms and discrepancies in reported findings. This synthesis could clarify AnxA2's role in viral entry, replication, and release. The review focuses on epithelial cell-targeting viruses, which are a major cause of human disease. The goal is to determine whether AnxA2 acts as a general host factor or has virus-specific functions. The authors also aim to reveal gaps in current research that could guide future investigations. This approach allows for a more comprehensive understanding of AnxA2's role in viral pathogenesis.

The authors conducted a literature review focusing on AnxA2's role in viral infections. They selected studies involving epithelial cell-targeting viruses and analyzed the reported functions of AnxA2. The review included both monomeric and heterotetrameric forms of AnxA2. The authors examined how AnxA2 interacts with viral components at different stages of infection. They assessed findings related to AnxA2's role in endocytosis, membrane organization, and RNA regulation. The review also considered the structural context of AnxA2 in the cell. The authors synthesized data to identify patterns and inconsistencies across studies. This approach allowed them to address the fragmented nature of prior research.

AnxA2 is frequently reported to support viral entry through endocytosis and membrane rearrangement. The AnxA2/S100A10 heterotetramer (A2t) has been implicated in membrane domain organization during viral entry. Some studies suggest that AnxA2 facilitates viral genome release into the cytoplasm. Others report that AnxA2 regulates RNA binding, potentially influencing viral replication. The protein's presence on the plasma membrane suggests a role in viral egress. However, findings on AnxA2's role in viral replication vary across studies. Some viruses appear to rely more heavily on AnxA2 than others. The review highlights discrepancies in reported functions depending on the virus and cell type.

AnxA2 appears to function as a host factor in multiple viral infections. The protein's role in membrane organization and RNA regulation supports viral lifecycle stages. However, the exact mechanisms remain inconsistent across studies. The authors propose that AnxA2's function may vary depending on the virus and cell type. The review suggests that AnxA2 may facilitate viral entry and egress through membrane remodeling. The AnxA2/S100A10 heterotetramer may be particularly important in these processes. The authors suggest that further research is needed to clarify AnxA2's role in specific viral infections. This review provides a foundation for future studies on AnxA2's function in viral pathogenesis.