Annexin Proteins
Annexin Proteins - Related Videos
09:09
Annexin V and Propidium Iodide Labeling
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2023
Staining with annexin V and propidium iodide (PI) provides researchers with a way to identify different types of cell death—either necrosis or apoptosis. This technique relies on two components. The first, annexin V, is a protein that binds certain phospholipids called phosphatidylserines, which normally occur only in the inner, cytoplasm-facing leaflet of a cell’s membrane, but become “flipped” to the outer leaflet during the early stages of apoptosis. The second component is the DNA-binding...
04:21
Annexin V Binding Assay: A Fluorescence-Based Technique to Identify Apoptotic Erythrocytes via Phosphatidylserine Labeling
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2025
In this video, we demonstrate the Annexin V binding assay to measure the degree of eryptosis, erythrocyte programmed cell death, using fluorescent Annexin V staining. Apoptotic erythrocytes demonstrate phosphatidylserine translocation from the inner to the outer leaflet of the cell membrane, causing the fluorophore-tagged Annexin V to bind to the translocated phosphatidylserine, thereby emitting a fluorescent signal.
07:34
Modified Annexin V/Propidium Iodide Apoptosis Assay For Accurate Assessment of Cell Death
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Cited by 543 •
2011
An accurate method for the assessment of cell death is described. The protocol improves upon conventional Annexin V/ propidium iodide (PI) protocols, which display up to 40% false- positive events in cell lines and primary cells from a broad range of animal models.
07:11
Dissipative Microgravimetry to Study the Binding Dynamics of the Phospholipid Binding Protein Annexin A2 to Solid-supported Lipid Bilayers Using a Quartz Resonator
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Cited by 5 •
2018
Here, we present an experimental protocol that can be employed to determine the binding affinities and mode of interaction of label-free phospholipid-binding protein annexin A2 with immobilized solid-supported bilayers (SLB) by simultaneously measuring the mass uptake and the viscoelastic properties of the protein annexin A2.
08:46
Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli
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Cited by 34 •
2015
A streamlined approach to screening for the expression of recombinant membrane proteins in Escherichia coli based on fusion to green fluorescent protein is presented.
FAQs
Calcium ions act as a reversible switch for membrane association. When calcium coordinates with annexin domains, the proteins bind negatively charged phospholipid surfaces; when the interaction is not maintained, binding can be reversed. This conditional attachment allows annexins to respond to changing cellular conditions while connecting membrane surfaces with signaling and structural activities.
Annexin domains are important because they provide the calcium-coordinating architecture that supports phospholipid binding. Once recruited to a membrane, an annexin can help organize membrane-associated protein complexes rather than acting only as an isolated binding molecule. This organization offers a mechanistic link between calcium signals, membrane structure, and the assembly of functional cellular machinery.
Although annexins share conserved membrane-binding features, individual family members have distinct functions. Consequently, findings about one annexin cannot automatically be generalized to the entire family. Comparing family members in processes such as repair, trafficking, cytoskeletal organization, inflammation, or apoptosis helps identify which cellular outcomes reflect shared membrane association and which depend on member-specific roles.
These studies can show how changes in calcium-dependent membrane association relate to membrane dynamics and cellular stress responses. By focusing on reversible binding to negatively charged phospholipids, researchers can connect a molecular interaction to broader effects such as membrane repair, signaling, or apoptosis. The approach therefore links biochemical behavior with cell-level outcomes.
Annexin research is relevant to membrane repair, vesicle trafficking, cytoskeletal organization, inflammation, and apoptosis. These areas reflect different ways membrane-associated proteins can influence cell behavior: maintaining damaged membranes, moving vesicles, coordinating structural elements, shaping inflammatory responses, or participating in programmed cell death. The specific emphasis depends on the family member under study.
Their roles in membrane dynamics, stress responses, inflammation, and apoptosis make annexins relevant to disease-mechanism studies. Researchers also investigate them as potential biomarkers, meaning measurable indicators associated with biological or disease states, and as possible components of therapeutic strategies. These applications depend on clarifying individual annexin functions rather than treating the family as uniform.