Endocytic Protein Colocalization
Endocytic Protein Colocalization - Related Videos
11:32
Measuring Plasma Membrane Protein Endocytic Rates by Reversible Biotinylation
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Cited by 23 •
2009
Regulated endocytosis governs the cell surface expression levels of the majority of membrane proteins. Here we utilize reducible, membrane impermeant biotinylation reagents to measure the endocytic rate of the dopamine transporter (DAT), a polytopic membrane protein. The method facilitates a straightforward approach to measuring the endocytic rate of most plasma membrane proteins.
03:13
Immunostaining to Visualize Viral Antigen and Host Protein Colocalization in the Insect Gut
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2026
Source: Zhang, L., et al. Immunofluorescent Labeling of Plant Virus and Insect Vector Proteins in Hemipteran Guts. J. Vis. Exp. (2021)The video demonstrates the preparation of gut tissue from a plant virus–infected insect vector for fluorescence imaging. Fixed guts were washed, permeabilized, and incubated with two fluorescent antibodies in a blocking solution—one targeting a viral antigen in vesicles, the other a vesicle-associated membrane protein. The tissue was counterstained for actin...
08:02
Live-cell Imaging of Endocytic Transport using Functionalized Nanobodies in Cultured Cells
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Cited by 1 •
2025
Endocytic and retrograde transport of proteins from the plasma membrane to the trans-Golgi network is essential to maintaining membrane homeostasis and regulating signaling. Here, we describe a method to image and quantify endocytic transport of transmembrane cargo proteins by live-cell microscopy using derivatized anti-GFP nanobodies in HeLa cells.
10:42
Determining Cell-surface Expression and Endocytic Rate of Proteins in Primary Astrocyte Cultures Using Biotinylation
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Cited by 6 •
2017
Two biotinylation-based methods, designed for determining the cell-surface expression and endocytic rate of proteins expressed at the plasma membrane, are presented in this report.
05:13
Density Gradient Ultracentrifugation for Investigating Endocytic Recycling in Mammalian Cells
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Cited by 1 •
2021
This paper aims to present a protocol for preparing recycling endosomes from mammalian cells using sucrose density gradient ultracentrifugation.
FAQs
Colocalization indicates that labeled proteins occupy overlapping cellular locations, but it does not by itself establish direct physical binding. In endocytic protein colocalization, researchers compare fluorescent signals within endocytic vesicles or trafficking pathways and interpret overlap as evidence that proteins may share a compartment or route. This distinction prevents spatial association from being overstated as molecular interaction.
Spatial overlap becomes more informative when it is examined across time. If two signals appear together and later separate, the pattern can indicate movement through or exit from a shared endocytic route; persistent overlap may indicate continued residence in the same compartment. Temporal comparison therefore helps distinguish transient co-occurrence from sustained association during trafficking.
Researchers use distinct fluorescent markers to distinguish proteins during imaging. Comparing where each signal appears helps determine whether the proteins occupy the same vesicle, compartment, or trafficking route. This spatial comparison supports analysis of shared localization without requiring the signals to be treated as identical, preserving the ability to follow each protein separately.
In immune cells, these measurements can connect receptor internalization with downstream intracellular localization. Comparing receptor-associated signals with endocytic compartments may show where uptake occurs, while tracking other labeled proteins can place microbial factors within the same trafficking context. This helps relate compartmental organization to antigen processing, signaling regulation, and cellular responses to infection.
A basic workflow starts by assigning different fluorescent markers to the proteins of interest, followed by fluorescence-microscopy imaging of the relevant cells. Researchers then compare the position of each signal and, when the experiment includes multiple observations, their timing. The resulting overlap patterns are interpreted in relation to endocytic vesicles or trafficking pathways.
During infection studies, the method can follow where microbial factors appear relative to host endocytic structures. In parallel, it can help examine pathogen entry by comparing microbial signals with proteins associated with uptake or intracellular trafficking. These observations provide a spatial and temporal view of infection-related localization, rather than relying only on whether a factor is present.
Within immunology and infection, observed colocalization can be used to investigate phagosome maturation and the cellular handling of internalized material. It can also help connect intracellular localization with antigen-processing pathways and signaling regulation. The main outcome is a map of where proteins or microbial factors appear during uptake and trafficking, which can clarify immune-cell responses.