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I agree. Live cell staining (without fixation or permeabilisation) circumvents this problem.
Julia
 
 
Yes, you do get partial permeabilisation with para formaldehyde.
You can stain unfixed non permeabilised cells to look at membrane proteins.

Michelle

On 21 Aug 2012, at 20:38, "Trop, Stefanie A." <[log in to unmask]> wrote:

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> Dear list,
>
> Has anyone had experience with paraformaldehyde permeabilizing mammalian cells? One of my labmates fixed cells grown on coverslips with a fresh aliquot of 4% paraformaldehyde that we made from powder and had stored at -20C, and had strong staining with antibodies that I would not expect to be present on the membrane, specifically EEA1 and ubiquitin-conjugated proteins. He did not add any alcohols nor detergents during any subsequent staining steps. Thanks for any assistance you can offer!
>
> Yours,
> Stefanie Trop
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> _____________________________________________
> Stefanie Trop, PhD Candidate
> Johns Hopkins Bloomberg School of Public Health
> Department of Molecular Microbiology and Immunology
> Laboratory of Jelena Levitskaya
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