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Figure 5.
Figure 5. Functional role of conformation-restrained tandem
PDZ repeats in PSD-95. (A) Extending the PDZ12 linker by
introducing flexible amino acid residues reduces the size of the
Kv1.4 channel clusters mediated by N-PDZ12. Myc-tagged
constructs N-PDZ1-2 wild-type (N-PDZ12), the deletion mutant of
N-PDZ12 (N-PDZ12Del) and the insertion mutant of N-PDZ12
(N-PDZ1-2Ins) were co-transfected in COS7 cells with potassium
channel subunit Kv1.4. Cells cotransfected with different
constructs, as indicated, were fixed two days after transfection
and stained with Kv1.4 antibodies to visualize the potassium
channel clusters. The schematics of the deletions and insertion
mutations used in this study are shown. Insets show
higher-magnification views of Kv1.4 clusters. (B) Frequency
distribution (left) and mean values (right) of Kv1.4 cluster
areas mediated by N-PDZ12, N-PDZ12(Del) and N-PDZ12(Ins),
measured from at least ten cells for each construct. The scale
bars represent 5 µm or 15 µm for the insets. An
asterisk (*) indicates significance at p <0.01 in an unpaired,
two-tailed Student's t-test.
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