Fig. 8. Confocal analysis of MDCK 10B cells expressing InsP₃R-1-EGFP. (A) Localization of InsP₃R-1-EGFP and proteins of the endoplasmic reticulum in non-polarized (3 days) and polarized (12 days) 10B cells. For the 3-day culture an xy section taken in the middle of the cell layer is presented; note the more intense perinuclear staining of InsP₃R-1-EGFP, particularly visible in the merged image. For the 12-day culture a complete compiled z series of 27 xy sections taken in 0.3 µm steps is shown. (B) Localization of both types of InsP₃-R in polarized 10B cells. The staining obtained for each protein is presented in addition to the merged images. The images shown correspond to a complete compiled z series of 30 xy sections taken in 0.3 µm steps with an xz section taken at the plane indicated by the arrow on the corresponding compilation. (C) Localization of InsP₃R-1-EGFP and ER proteins in polarized 10B cells: an xz section of cells stained with a polyclonal antibody directed against a bulk of ER proteins is shown. The staining for each protein and the merge image are presented. InsP₃R-1-EGFP is mostly present at the upper part of the lateral pole, whereas ER proteins are widely distributed around the nucleus, in the whole cytoplasm. (D) Localization of InsP₃R-1-EGFP and cadherin(s) in polarized 10B cells: an xz section of cells stained with anti-pan cadherin is shown, the staining obtained for each protein being presented in addition to the merged image. Note the restricted distribution of InsP₃-R-1-EGFP at the top of the lateral pole. (E) Localization of InsP₃R-1-EGFP and sec6 in polarized 10B cells: an xz section is shown with the staining for each protein and the merged image. (F) Localization of InsP₃R-1-EGFP in living polarized 10B cells. An xy section and an xz one taken through the cells at the plane indicated by the arrow are presented. The top and the bottom of the cell layer shown in all the xz sections are indicated by asterisks (*). Bars, 10 µm.