Fig. 6. The cytoplasmic domain of NPP3 is responsible for Lubrol-DRM association. (A-C) Scanning confocal micrographs of MDCK cells stably transfected with cDNAs of the indicated constructs. Cells were treated as in Fig. 2. Bars, 10 µm. (D-F) DRM association of NPP1-TmNPP3 (D), NPP3-CytoNPP1 (E), and NPP1-CytoNPP3 (F). Cell homogenates were extracted and floated on sucrose gradients and the distribution of the proteins was analyzed as in Fig. 2. Typical immunoblots are shown. Bar chart values are means ± s.d. of at least three determinations.