Effects on the subcellular localization of PKCε
by deletion of the actin-binding site. SK-N-BE(2) cells transfected
with vector encoding full-length PKCε (A and C–E) and PKCε without
the actin-binding site (B and F–H), both fused to EGFP. Transfected
cells were subjected to subcellular fractionation (A and B) and divided
into a cytosolic fraction (C), a membrane fraction (M), and a
cytoskeletal fraction (S), which were analyzed with Western blotting
with antibodies directed toward PKCε. Immunoblots from
three individual experiments were quantified and data are presented as
percentage of PKCε in each fraction out of total PKCε content.
White bars represent endogenous PKCε and black bars represent
EGFP-tagged PKCε variants. Cells expressing wild-type PKCε (C–E)
and PKCε without actin-binding site (F-H) were fixed, and F-actin was
stained with Alexa Fluor 546-conjugated phalloidin and by using
confocal microscopy, a colocalization analysis was done. The images
depict PKCε-EGFP (C and F), F-actin (D and G), and pixels that
represent colocalization of PKCε and F-actin (E and H). Arrows
highlight areas with cortical F-actin. The amount of
phalloidin-positive pixels in the cortical cytoskeleton that was also
EGFP-positive was 24% (wild-type PKCε) and 14% (PKCε with deleted
actin-binding site) by using LaserPix software.