Figure 9.

Endosomal Orai1 translocates to the cell membrane after store depletion. (A) Distribution of Orai1 and STIM1 in oocytes before and after store depletion with 5 mM TPEN, which results in coclustering of STIM1 and Orai1 at the plasma membrane–ER junction. In addition, rare coclustering events are detected deep in the cell (1.2 µm), as indicated by the boxes and matching white bar in the orthogonal section. Deep focal plane and orthogonal sections are shown. (B) Same experimental approach as in A except that images were taken at the GVBD stage of oocyte maturation. Store depletion (+TPEN) leads to Orai1–STIM1 coclustering at the cell membrane and deep in the cell at the endosome–ER interface (arrowheads and boxes). The position of the boxes is indicated by the bar in the orthogonal view. Bars, 5 µm.