Fig. 5.

Kinase-dependent inhibition of STIM1 clustering during meiosis. (A) Signaling cascade regulating Xenopus oocyte maturation. Oocytes expressing GFP–Orai1 and mCherry–STIM1 were untreated (Ooc) or treated with 5 μg/mL progesterone (egg); injected with Mos RNA (10 ng, Mos); injected with Wee1 RNA (10 ng) and incubated overnight before Mos RNA injection (Wee-Mos); injected with cyclin B1 RNA (10 ng, Cycl); or pretreated with U0126 (50 μM) for 1 h before cyclin B1 RNA injection (U-Cycl). Orai internalization is shown as a confocal section deep into the cell. STIM1 clustering is shown only after store depletion (+TPEN) (Scale bar, 2 μm.) The examples shown are representative of 6–8 cells for each treatment. (C) Lysates from cells analyzed in B tested for MAPK (P-MAPK) and Cdc2 (P-cdc2) phosphorylation.