Apoptosis Resource: Changes in the Plasma Membrane
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Measurement of Apoptosis-Induced Changes at the Plasma Membrane
In normal viable cells, phosphatidyl serine (PS) is located on the cytoplasmic side of the cell membrane. Upon induction of apoptosis, rapid alterations in the organization of phospholipids occur, leading to translocation of PS to the outer leaflet of the plasma membrane. PS translocation to the cell surface is one of the earliest events in apoptosis and precedes nuclear breakdown, DNA fragmentation, and membrane blebbing. Recognition of PS by phagocytes in vivo results in the removal of apoptotic cells, thus apoptosis is not associated with the local inflammatory response which generally accompanies necrosis. Annexin V binding to PS can be used as a marker of early-stage apoptosis. In vitro detection of externalized PS can be achieved through interaction with Annexin V, a Ca2+-dependent protein. In the presence of calcium, rapid high-affinity binding of Annexin V to PS occurs. Annexin V is typically conjugated to a fluorochrome for easy indentification of apoptotic cells by flow cytometry or immunofluorescence microscopy.
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| Measurement of Changes at the Plasma Membrane: Annexin V Kits |
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Number of Tests or Samples |
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| Annexin V-Biotin Apoptosis Detection Kit II |
FC, IF |
Intact cells |
20 Tests |
CBA058 |
| Annexin V-FITC Apoptosis Detection Kit |
FC, IF |
Intact cells |
100 Tests |
PF032 |
| Annexin V-Biotin Apoptosis Detection Kit |
FC, IF |
Intact cells |
100 Tests |
PF036 |
| Annexin V-FITC Apoptosis Detection Kit II |
FC, IF |
Intact cells |
20 Tests |
CBA059 |
| Annexin V-PE Apoptosis Detection Kit |
FC, IF |
Intact cells |
25 or 100 Tests |
CBA060 |
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Annexin V-FITC Apoptosis Detection Kit Cat. No. PF032
Viable cells do not bind Annexin V-FITC or Propidium Iodide (PI) as reflected in the lower left-hand quadrant of the dot plot. Early apoptotic cells with exposed PS but intact cell membranes bind Annexin VFITC, but exclude PI. Fluorescence from this population is reported in the lower right-hand quadrant. Necrotic or apoptotic cells in terminal stages will be both Annexin V-FITC and PI positive and are reported in the upper right-hand quadrant. Note that a small percentage of normal cell death should be expected in routine cultures of untreated cells. | |
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| Measurement of Changes at the Plasma Membrane: Fas and Fas-ligand Kits |
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Number of Tests or Samples |
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| Fas Ligand ELISA Kit |
ELISA |
Cell lysates, tissue culture medium, serum, and plasma |
96 Tests |
QIA27 |
| Fas/APO-1 ELISA Kit |
ELISA |
cell lysates, tissue culture supernatant, serum, or plasma |
96 Tests |
QIA24 |
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| Measurement of Plasma Membrane Integrity Using Vital Dyes |
| Under normal conditions vital dyes are not capable of crossing the plasma membrane of intact non-apoptotic cells. When the membrane properties are compromised, during apoptosis or necrosis, these dyes cross the cell membrane and bind cellular components. This principle can be used as a simple way of assessing the integrity of the plasma membrane. |
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| Useful Tools for Measuring Changes at the Plasma Membrane |
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| Actinomycin D, 7-Amino- |
Intact Cells |
129935 |
| Live/Dead Double Staining Kit |
Cell suspensions or adherent cells |
QIA76 |
| Propidium Iodide |
Intact Cells |
537059 |
| Propidium Iodide Solution |
Intact Cells |
537060 |
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