Fig. 3. PtdIns(4,5)P₂ is required for Rab5 localization and yolk endocytosis. (A-C) Rab5 localization during oogenesis in wt egg chambers. (A) From germarium (upper left) to stage 6 (bottom right); (B) stage 8; (C) stage 10. Note the recruitment of Rab5 in the oocyte cortical region during the vitellogenic stages (B,C). (D-G) Rab5 and PH(PLC)-GFP localization in wt stage 10 egg chambers. (F; red in D,G) Rab5; (E; green in D,G) PH(PLC)-GFP. (E-G) Correspond to the region inside the boxed area in D. Rab5 is visible at and in a narrow region below the oocyte PM (F,G; arrow). (H-S) PH(PLC)-GFP, Lycopersicon esculentum (L.e.) Lectin and Rab5 localization in control (H-M) and sktl⁵/sktl^2.3 (N-S) stage 10 egg chambers. (I,K,O,Q; green in H,J,N,P) PH(PLC)-GFP; (L,R; red in H,J,N,P) L.e. lectin; (M,S) Rab5. At the oocyte PM, when compared with wt, the PH(PLC)-GFP signal is reduced in sktl⁵/sktl^2.3 mutants, whereas L.e. lectin, highlighting the PM, is unaffected (arrows in I,J-L,O,P-R). The recruitment of Rab5 in the oocyte cortical region is impaired in sktl⁵/sktl^2.3 mutants when compared with controls (compare M and S). (T,U) Yl localization in control (T) and sktl⁵/sktl^2.3 mutant (U) stage 10 egg chambers. Green, PH(PLC)-GFP; red, Yl. The localization of Yl in sktl⁵/sktl^2.3 is similar to control. (V,W) Electron micrographs of stage 9 egg chambers. (V) wt; (W) sktl^2.3 GLCs. Note that, in sktl^2.3 GLCs, unlike in the control, no dark yolk granules are visible in the oocyte cytoplasm (W). oo, oocyte; fc, follicle cells; nc, nurse cells.