Nuclear Staining + Protein Isolation??

[Samantha]

Hi,

i had transfected wells with pEGFP-my gene (which is localised in the
nucleus)
then..i wanted to stain the nucleus to check the transfection efficiency
i used3.7% paraformaldehyde to fix cells and 0.05% triton-x 100 to
permealise the membrane (All in 1X PBS and the cells were wahsed with 1X
PBS)
after the staining, i wanted to isolate the proteins
so i tried to use the normal protocol to prep the proteins (that protocol is
fine for other proteins which had not been stained: just used trysin to
trysinize the cells and lysis buffer we commonly use)
but i could not harvest the proteins

** I want to ask it is fine to stain the cells and then harves the proteins?
(I ve tried to find the solutions on the web, but I couldnt)

Thank you very much.

Samantha