Fig. 5. Trapping of Grk^DC protein at the plasma membrane through inactivation of the Drosophila Dynamin homologue Shibire requires Cni function. (A) shi^TS; grk^DC/CyO egg chamber incubated at the permissive temperature (25°C). Grk staining at the membrane is limited to the vicinity of the nucleus. Ovaries preincubated in Schneider's medium exhibit higher than usual background, irrespective of their genotype. (B) shi^TS; cni^AR55/CyO egg chamber incubated at 25°C. Grk is distributed in the wild-type pattern. (C) shi^TS; cni^AR55/grk^DC Df(2L)H60 egg chamber incubated at 25°C. Grk is diffusely distributed throughout the oocyte. (D) Incubation at 32°C blocks endocytosis in shi^TS; grk^DC /CyO oocytes. Membrane tethered Grk^DC protein accumulates at the oolemma. (E) Blocking endocytosis in shi^TS; cni^AR55/CyO ovaries has no effect on the wild-type Grk protein not anchored to the oocyte plasma membrane. (F) shi^TS; cni^AR55/grk^DC Df(2L)H60 egg chamber incubated at the restrictive temperature. In the absence of cni, Grk^DC protein cannot be trapped at the plasma membrane but remains mislocalized to the interior of the oocyte.