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. 2005 May 10;388(Pt 1):355–362. doi: 10.1042/BJ20041447

Figure 3. Cell-surface levels of other Kv1 members are governed by similar amino acid pairs in their deep pore regions.

Figure 3

Transiently transfected CHO cells were analysed for their cell-surface protein levels and their total protein levels by biotinylation/immunoblotting and immunoblotting respectively. The Kv1 protein's whole cell immunofluorescence localization patterns in transiently transfected permeabilized COS7 cells are also shown. (A) Cell-surface protein profile of Kv1.2 constructs with different amino acid pairs in the deep pore by biotinylation/immunoblotting. (B) Group data for cell-surface protein levels. Normalized cell-surface protein levels by biotinylation and immunoblotting. The Kv1.2S371T/V381K construct value was taken as 100.0±S.E.M. and the other construct values were normalized to it (n=3). (C) Cell total protein levels by immunoblotting (immunoblots are not shown). The Kv1.2S371T/V381K construct value was taken as 100.0±S.E.M. and the other construct values were normalized to it (n=3). (D) Relative surface expression levels obtained by dividing the surface values in (B) by the total values in (C). (E) Immunofluorescence localization pattern of Kv1.2 constructs in COS7 cells. Scale bar, 10 μm. (F) Cell-surface protein profile of Kv1.4 constructs with different amino acid pairs in the deep pore by biotinylation/immunoblotting. Kv1.4K533R and Kv1.4K533H constructs have the same amino acid pair as Kv1.5 (Thr/Arg) and Kv1.3 (Thr/His) respectively (see Figure 1). (G) Group data for cell-surface protein levels from (F). The Kv1.4 construct value was taken as 100.0±S.E.M. and the other construct values were normalized to it (n=3). (H) Group data for cell total protein levels (immunoblots are not shown). The Kv1.4 construct value was taken as 100.0±S.E.M. and the other construct values were normalized to it (n=3). (I) Relative surface expression levels obtained by dividing the surface values in (G) by the total values in (H). (J) Immunofluorescence localization pattern of Kv1.4 constructs in COS7 cells. Scale bar, 10 μm. Note that, in immunofluorescence micrographs, the important parameter is the localization pattern and not the signal intensity.