Subcellular redistribution of HIP14L-GFP fusion protein in response to
magnesium. Immunofluorescence staining of HIP14L-GFP fusion protein of
transiently expressing MDCK epithelial cells. A, Golgi localization
of HIP14L-GFP. Cells were cultured in media containing normal magnesium
concentration, fixed, and incubated with GFP antibody (HIP14L-GFP)
and the Golgi marker, GM130 (GM130). The merged image demonstrates
HIP14L-GFP and GM130 colocalization (Merge). A phaloidin overlay of
the merged image shows the surface membrane (Phaloidin). B,
there was very little submembrane HIP14L protein in MDCK cells cultured in
normal magnesium media. The image is of A digitally enlarged 4 times
with each of the respective stains. C, Golgi localization of
HIP14L-GFP in cells cultured in low magnesium media. Cells were fixed and
incubated with GFP antibody (HIP14L-GFP), GM130 (GM130), GFP
and GM130 merged (Merge), and phaloidin (Phaloidin). Note,
the increase in Golgi HIP14L-GFP and the evident appearance of subplasma
membrane HIP14L-GFP protein. D, submembrane location of post-Golgi
HIP14L-GFP protein with low magnesium. The image is of C digitally
enlarged 4 times with each of the respective stains. Note, the predominant
submembrane localization of post-Golgi HIP14L-GFP protein. E, absence
of HIP14L-GFP protein in early recycling endosomes supporting the notion that
the HIP14L protein does not traffic to the plasma membrane. MDCK cells were
cultured in normal media with normal magnesium concentration. The images
comprise HIP14L-GFP staining (HIP14L-GFP), Rab5 (Rab5),
HIP14L-GFP and Rab5 merged image (Merge), and the phaloidin overlay
image (Phaloidin). F, absence of HIP14L-GFP protein in early
recycling endosomes. MDCK cells were cultured in media with low magnesium.
HIP14L-GFP staining (HIP14L-GFP), Rab5 (indicated as Rab5),
merged image (Merge), and the phaloidin overlay image
(Phaloidin) are shown. G, control MDCK cells transfected
with GFP alone. H, magnesium-restricted MDCK cells transfected with
GFP alone. Changes in magnesium concentration do not alter GFP distribution.
All images are representative in excess of 30 cells for each condition.