The plasma membrane separates the interior of the cell from the extracellular environment. Its predominant components are proteins and lipids, and it is instrumental in signaling pathways as well as ionic homeostasis. It is a convenient marker of the cell boundary and, as such, a number of plasma membrane probes have been utilized for automated segmentation in HCS assays. Typically, lipophilic dyes are used as plasma membrane stains; however, they are internalized rapidly and thus permit only a very narrow window for imaging. Fluorescently labeled lectins (e.g., wheat germ agglutinin) are also widely used, although plasma membrane staining shows variation across cell types.

CellLight® reagents for plasma membrane

Use CellLight® reagents when you want to label the plasma membrane in live cells to follow the dynamics of cellular behavior. CellLight® proteins can be multiplexed with other fluorescent probes for analysis in live cells, or after fixation for colocalization studies. These ready-to-use constructs express fluorescent fusion proteins targeted using the myristoylation/palmitoylation sequence from Lck tyrosine kinase (0.9 kDa). Introducing CellLight® reagents involves a simple transfection step, and they work like cell stains with minimal toxicity or chemical disruption.

CellLight® Plasma Membrane-GFPEnlarge image
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WGA conjugates for live and fixed cells

Wheat germ agglutinin (WGA) is one of the most widely used lectins in cell biology. When conjugated to Alexa Fluor® dyes, wheat germ agglutinins are versatile cationic probes for detecting glycoconjugates, i.e., N-acetylglucosamine and N-acetylneuraminic acid (sialic acid) residues, on cell membranes. The conjugates are useful in fixed and live cells that have not been permeabilized, and the range of colors provides experimental flexibility for multiplexing and colocalization. WGA also serves as a retrograde tracer for neuronal mapping where it will also cross synapses.

Alexa Fluor® 350 wheat germ agglutininEnlarge image

CellMask™ stains

CellMask™ Plasma Membrane Stains allow fast and uniform labeling of the plasma membrane without the cell-type differences exhibited by lectins. These stains may be used as a segmentation tool for high-content screening, as well as to stain cellular plasma membranes for standard fluorescence microscopy. The stains survive fixation but not permeabilization, so they are not suitable for experiments that also involve probing internal targets via antibodies. A range of colors provides experimental flexibility for multiplexing and colocalization.

CellMask™ Deep Red plasma membrane stainEnlarge image
Selection guides
 
Readout
 Expression of fluorescent fusion protein
Target
 Localizes to a plasma membrane-associated kinase
Common filter set
DAPI
FITC
TRITC
Labels
CFP
GFP
RFP
Ex/Em (nm)
435/485
488/520
555/584
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Yes
Yes
Live cells
Yes
Yes
Yes
Fixed cells
No
No
No
Fixable
Yes
Yes
Yes
Platform
Imaging
Imaging
Imaging
Format
1 mL
1 mL
1 mL
Cat. No.
 
Readout
 High-performance fluorescent label with stable signal; resistant to photobleaching and pH change
Range
 Binds to N-acetylglucosamine and N-acetylneuraminic acid (sialic acid) residues on cell membranes
Common filter set
DAPI
FITC
TRITC
Labels
Alexa Fluor® 350
Alexa Fluor® 488
Alexa Fluor® 555
Ex/Em (nm)
346/442
495/519
555/565
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Yes
Yes
Live cells
Yes
Yes
Yes
Fixed cells
Yes
Yes
Yes
Fixable
Yes
Yes
Yes
Platform
Imaging 
Imaging 
 Imaging
Format
5 mg
5 mg
5 mg
Cat. No.
 
Readout
High-performance fluorescent label with stable signal; resistant to photobleaching and pH change
Range
Binds to N-acetylglucosamine and N-acetylneuraminic acid (sialic acid) residues on cell membranes
Common filter set
Texas Red®
Texas Red®
Cy®5
Cy®5.5
Labels
Alexa Fluor® 594
Alexa Fluor® 633
Alexa Fluor® 647
Alexa Fluor® 680
Ex/Em (nm)
590/617
632/647
650/668
679/702
Signal-to-noise ratio
Photostability
Multiplexing
Yes
Yes
Yes
Yes
Live cells
Yes
Yes
Yes
Yes
Fixed cells
Yes
Yes
Yes
Yes
Fixable
Yes
Yes
Yes
Yes
Platform
Imaging 
Imaging 
 Imaging
 Imaging
Format
5 mg
5 mg
5 mg
5 mg
Cat. No.
 
Readout
High-performance fluorescent label 
Target
Targets plasma membrane  
Common filter set
FITC
TRITC
Cy®5
Labels
CellMask™ Green
CellMask™ Orange
CellMask™ Deep Red
Ex/Em (nm)
522/535
554/567
649/666
Signal-to-noise ratio
Photostability
Bibliography
Multiplexing
Yes
Yes
Yes
Live cells
Yes
Yes
Yes
Fixed cells
No
No
No
Fixable
Yes
Yes
Yes
Platform
Imaging
Imaging
Imaging
Format
100 μL
100 μL
100 μL
Cat. No.
For Research Use Only. Not for use in diagnostic procedures.