| Aspect | Concise statement | Supporting retrieved sources |
|---|---|---|
| Identity/domains | **CHMP4B** is the human **charged multivesicular body protein 4B** encoded by **CHMP4B** (UniProt **Q9H444**), a member of the **ESCRT-III/SNF7 family**. CHMP4-family proteins share the Snf7 core architecture with N-terminal membrane-interacting regions and C-terminal regulatory/MIM-containing tails that support polymerization and VPS4 engagement. (pqac-00000003, pqac-00000004, pqac-00000006) | Park 2024, https://doi.org/10.1080/19768354.2024.2380294; Azad 2023, https://doi.org/10.1038/s41594-022-00867-8 |
| Core molecular function | CHMP4B is a **membrane-remodeling adaptor/scaffold**, not an enzyme: it polymerizes on membranes as part of **ESCRT-III** to drive **reverse-topology membrane constriction and scission**, especially during intralumenal vesicle formation and related sealing/fission reactions; VPS4 ATPase then remodels/disassembles the polymer. (pqac-00000001, pqac-00000003, pqac-00000004, pqac-00000005, pqac-00000006) | Park 2024, https://doi.org/10.1080/19768354.2024.2380294; Azad 2023, https://doi.org/10.1038/s41594-022-00867-8 |
| Key interactions | CHMP4B interacts functionally with **ALIX/PDCD6IP** via the CHMP4 C-terminus, works sequentially with **CHMP6**, **CHMP2A**, and **CHMP3** during ESCRT-III assembly, and depends on **VPS4A/B** for ATP-driven remodeling/disassembly; 2024 imaging also visualized CHMP4B together with **ALIX** and **VPS28/ESCRT-I** in helical scaffolds. (pqac-00000001, pqac-00000005, pqac-00000006, pqac-00000007, pqac-00000008) | Park 2024, https://doi.org/10.1080/19768354.2024.2380294; Spada 2024, https://doi.org/10.1101/2024.05.01.592080; Butt 2024, https://doi.org/10.1371/journal.ppat.1012300 |
| Cellular localizations | CHMP4B functions at **endosomes/MVBs**, the **midbody/intercellular bridge** during cytokinetic abscission, the **reforming nuclear envelope** in mitotic exit, and some **plasma-membrane/lysosomal repair** contexts; recent work also places CHMP4B in membrane-remodeling assemblies relevant to viral budding and endolysosomal quality control. (pqac-00000001, pqac-00000002, pqac-00000005, pqac-00000007, pqac-00000008) | Park 2024, https://doi.org/10.1080/19768354.2024.2380294; Spada 2024, https://doi.org/10.1101/2024.05.01.592080; Butt 2024, https://doi.org/10.1371/journal.ppat.1012300 |
| Pathways/processes | Best-supported pathways are **MVB/ILV biogenesis**, **endosomal sorting**, **cytokinetic abscission**, **nuclear envelope reformation/repair**, **autophagosome or phagophore closure**, **endosomal microautophagy**, and **virus budding/virus replication organelle remodeling**. (pqac-00000001, pqac-00000002, pqac-00000005, pqac-00000010) | Park 2024, https://doi.org/10.1080/19768354.2024.2380294; Kumar 2024, https://doi.org/10.3390/covid4090095 |
| Recent 2023-2024 developments | Recent advances include: (i) refined structural models for minimal ESCRT-III/VPS4 membrane scission machinery, which place SNF7-family CHMP4 proteins upstream of CHMP2/3 polymer maturation; (ii) 2024 super-resolution visualization of **helical ESCRT-I/ALIX/CHMP4B scaffolds in vivo**; and (iii) growing evidence that CHMP4B participates in **autophagy-related sealing**, **lysosomal/endosomal repair**, and **coronavirus replication-center formation**. (pqac-00000004, pqac-00000005, pqac-00000007, pqac-00000010, pqac-00000011) | Azad 2023, https://doi.org/10.1038/s41594-022-00867-8; Park 2024, https://doi.org/10.1080/19768354.2024.2380294; Spada 2024, https://doi.org/10.1101/2024.05.01.592080; Kumar 2024, https://doi.org/10.3390/covid4090095 |
| Disease/application links | CHMP4B has the clearest human genetic disease link to **cataract**, including **early-onset non-syndromic cataract** and **posterior polar cataract** in Open Targets evidence aggregation. Applied/real-world relevance also comes from ESCRT dependence in **viral infection**, **extracellular vesicle biology**, and membrane-repair pathways that are being explored as therapeutic intervention points. (pqac-00000009, pqac-00000010) | Open Targets query (2025 platform output for CHMP4B); Kumar 2024, https://doi.org/10.3390/covid4090095 |
| Quantitative/assay statistics | In Open Targets, CHMP4B shows association scores of **0.7111** for **early-onset non-syndromic cataract**, **0.6563** for **posterior polar cataract**, **0.5537** for **viral disease**, and **0.4620** for **HIV infection**; in a 2024 HCoV-229E study, CHMP4B perturbation significantly reduced viral genome readouts by RT-qPCR (**p = 0.024**), supporting a functional requirement in coronavirus replication-center biology. (pqac-00000009, pqac-00000010) | Open Targets query (2025 platform output for CHMP4B); Kumar 2024, https://doi.org/10.3390/covid4090095 |


*Table: This table summarizes verified functional annotation for human CHMP4B/UniProt Q9H444, including identity, mechanism, localization, pathways, recent developments, and disease links. It is useful as a compact evidence map grounded in the retrieved sources.*