Figure 6.

The TGFβ type II receptor basolateral localizing signal is dominant over the apical targeting signal in the influenza virus HA protein. (A) Influenza virus HA protein chimeras were constructed with terminal fragments of the T2R fused to the HA transmembrane domain. The full-length type II receptor (TGFβ RII) is provided for orientation and the location of the identified targeting sequence is indicated by a red *. (B–E) Fully polarized MDCK cell monolayers were transfected for 5 h with plasmids expressing either wild-type HA, an ICD-deleted HA protein (pHA-ICD), or chimeras consisting of pHA-ICD expressing type II receptor terminal fragments 548-567 or 484-567 (pHA+T2R548-567 and pHA+T2R484-567, respectively). Receptors and nuclei were visualized as described. Images are represented as horizontal XY flat sections focused at either the apical surface (top) or the central nuclei plains (middle), above lower perpendicular XZ cross sections through the plain of the cell.