Figure 1.

Isolation of HEK293 cell lines expressing mZIP4 mutant proteins. A, schematic diagram of the mZIP4 protein and mutations investigated in this study. Most of the extracellular N-terminal region (residues 5 to 330) of mZIP4 is deleted in ΔNED-mZIP4-HA. Another deletion mutation incorporating residues 398 to 410 is shown, as well as two mutations involving alanine substitutions introduced into two HTH sequences in the first extracellular loop. B, Western blot analysis of HEK293 cells stably expressing mZIP4 mutant proteins shown in A. Total cell lysates were immunoblotted with anti-HA antibodies to detect mZIP4-HA protein, or anti-tubulin antibodies as a control for protein loading. As a negative control, HEK293 cells were transfected with empty vector and grown in basal medium (lane 1).