Re: endocytosis for cell biology lab

Posted by Gudrun Ihrke on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Concentrating-bacteria-cells-for-microscope-visualization-tp6519025p6526264.html

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Tobias,

Unless you preincubate with lipoprotein-deficient serum, the LDL  
receptor will be downregulated. It would be much easier to use a small  
fluorescent dextran to label the endocytic pathway towards lysosomes:  
~3 min incubation will give you early endosomal staining, ~15-45 min  
late endosomal (best use a pulse of 10-15 min pulse and chase 15-30  
min for bright staining, >1h late endosomal/lysosomal staining (use  
also a pulse if you want to chase the dextran out of earlier  
compartments).

Gudrun

Gudrun Ihrke, Ph.D.
Research Assistant Professor
Department of Pharmacology (C2025)
Uniformed Services University School of Medicine
4301 Jones Bridge Road
Bethesda, MD  20814


On Jun 28, 2011, at 2:25 PM, Tobias Baskin wrote:

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>
> Hi all,
> This is not a "confocal" question but rather a cell bio/microscopy  
> related one. Nevertheless, I am hoping someone will be able to answer.
>
> I co-teach a cell biology lab course where students learn how to  
> use conventional epi fluorescence and video microscopy. We have a  
> variety of "cells in action" labs for them to do, one of these being  
> endocytosis. As markers, e have used labeled-transferrin and also  
> DiI labeled LDL, with the idea being  that the transferrin is  
> recycled back to the plasma membrane whereas the LDL moves into  
> lysosomes. While the transferrin labeling seems to work more or less  
> as expected, results with the DiI LDL are erratic. Sometimes there  
> is no labeling at all, and we never have seen what looks like deep  
> internal labeling in putative lysosomes.
>
> We plan to troubleshoot later this summer but as none of us have  
> studied endocytosis, we have no first hand experience. I am  
> wondering if anyone out there knows of a tried and true endocytosis  
> cell bio lab? Or perhaps knows about some tricks for handling DiI  
> LDL. Or perhaps it is a matter of a good cell line -- we work  
> typically with a 3T3 fibroblasts or LLCPK epithelial cells (with  
> equally dismal results for the DiI LDL endocytosis).
>
> Thanks in advance for any suggestions.
>
> As ever
> Tobias Baskin
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