Spike Endocytosis
Spike Endocytosis - Related Videos
09:27
An Introduction to Endocytosis and Exocytosis
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2023
Cells can take in substances from the extracellular environment by endocytosis and actively release molecules into it by exocytosis. Such processes involve lipid membrane-bound sacs called vesicles. Knowledge of the molecular architecture and mechanisms of both is key to understanding normal cell physiology, as well as the disease states that arise when they become defective. This video will first briefly review a few pivotal discoveries in the history of endo- and exocytosis research. Next,...
01:16
Endocytosis
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2023
Eukaryotic cells acquire nutrients for growth and proliferation. Nutrients and other molecules that require degradation are internalized from the extracellular space by a process called endocytosis. The term ‘endocytosis' was first coined by Christian de Duve in 1963. Endocytosis always begins with the plasma membrane enclosing an incoming molecule to form a transport vesicle which, in some cases, can be coated with a protein called ‘clathrin.' Endocytosed material is either sorted through...
02:46
Visualizing Dose-Dependent Spike Protein Uptake with Quantum Dot Conjugates
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2026
Source: Tran, B. N., et. al. High-throughput Confocal Imaging of Quantum Dot-Conjugated SARS-CoV-2 Spike Trimers to Track Binding and Endocytosis in HEK293T Cells. J. Vis. Exp. (2022)This video demonstrates the use of quantum dot–conjugated spike protein (QD-Spike) to visualize dose-dependent viral entry in ACE2-GFP–expressing cells. Confocal imaging captures the internalization of QD-Spike via receptor-mediated endocytosis, modeling early coronavirus entry.
02:19
Triggering a Closed-Loop Stimulation by Neuron Spiking Activity
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2025
This video demonstrates the operation of closed-loop stimulation in a rat with a surgically implanted device to record neural activity. Neuronal signals are first recorded and analyzed. Template waveforms are then uploaded, and parameters are defined to trigger closed-loop stimulation.
01:28
The Early Endosome: Endocytosis of Transferrin
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2023
Essential proteins such as insulin or low-density lipoprotein (LDL) and micronutrients such as iron enter a eukaryotic cell through receptor-mediated endocytosis. Subsequently, the early endosomes fuse with the vesicles containing such receptor-ligand complexes and play a vital role in sorting the incoming ligands and receptors. While the ligands are either degraded inside the vesicle or released into the cytosol, their receptors are returned to the plasma membrane for further rounds of...
FAQs
Receptor engagement helps determine whether spike is internalized and what follows inside the cell. Once spike binds a host-cell receptor, the membrane response places the protein in an endocytic vesicle rather than leaving it at the cell surface. This creates a regulated route into endosomes, where subsequent environmental changes can influence viral entry and intracellular handling.
Endosomal acidification and proteolytic activity can act as activating conditions for spike. As the vesicle matures, its changing environment may alter spike structure, potentially exposing or enabling features needed for downstream membrane fusion. Consequently, uptake alone does not establish productive entry: the intracellular state of the endosome helps determine whether internalized spike can progress toward fusion.
Host factors influence spike endocytosis at more than one stage. Receptor availability affects initial binding, while cellular regulators of endocytic trafficking can shape vesicle formation, endosome maturation, and the fate of internalized protein. These controls help explain why receptor biology and host regulation are central to understanding differences in viral entry and antigen handling.
An uptake-and-trafficking assay can follow spike after it leaves the cell surface and enters intracellular compartments. The central measurements are how much spike is internalized and where it travels as endosomes mature. Such assays can distinguish surface association from intracellular trafficking and provide evidence about steps that precede membrane fusion, without treating uptake as proof of infection.
Researchers can apply spike endocytosis studies to several questions in biology. They can examine how host receptors and regulatory factors control enveloped-virus entry, evaluate points where antiviral strategies might act, and assess how antigen trafficking may affect immune recognition. The same framework informs vaccine antigen design by revealing how intracellular handling influences the fate of spike.
Within biology, the pathway connects cell-surface receptor biology with intracellular trafficking and viral membrane fusion. It also provides a way to study how a viral antigen moves through cells, which is relevant to immune recognition. Interpreting results requires keeping these outcomes separate: increased uptake may indicate altered trafficking or receptor behavior, whereas fusion-related consequences depend on endosomal conditions.