Human phospholamban null results in lethal dilated cardiomyopathy revealing a critical difference between mouse and human
J. Clin. Invest. Kobra Haghighi, et al. 111:869 doi:10.1172/JCI17892 [
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Figure 5Expression and localization of PLN-WT and PLN-L39stop mutant in HEK-293 cells. (
a) Immunoblot analyses of endoplasmic reticulum microsomes (left panel) and insoluble fractions (right panel) obtained at 24 and 48 hours after transfections. Note the absence of PLN-L39stop in the endoplasmic reticulum fraction, although detectable protein levels are found in the insoluble fraction. PLN
p, PLN pentamer; PLN
m, PLN monomer. (
b) Quantitation of the number of fluorescent cells on PLN-WT and PLN-L39stop transfected coverslips. Cultures were transfected with equal amounts of plasmid DNA, and 48 hours later the number of fluorescent cells was counted on the entire coverslip. (
c) Immunofluorescence of PLN-WT and PLN-L39stop transfected cells analyzed by confocal microscopy 48 hours after transfection. In PLN-WT transfected cells, immunofluorescence is exclusively in the endoplasmic reticulum, whereas a clearly distinct and plasma membrane–associated staining pattern is observed in the PLN-L39stop transfected cells. Scale bar, 30 μm. (
d) Fluorescence intensity was quantitated using available Leica software. For these assays, a straight profile line was drawn across the center of the cell and fluorescence amplitude was plotted. Arrows mark the edge of the cell and asterisks mark the ER. In PLN-WT transfected cells (upper panel), immunofluorescence is found within the interior of the cell, whereas in PLN-L39stop transfected cells (lower panel), staining is found enriched at the outer edge of the cell.