(A) An interphase ER network was generated with cytosol, DiIC18-prelabeled light membranes, and an energy regenerating system. Endogenous ATL was visualized by including 10.5 nM Alexa488-labeled, affinity-purified antibodies against Xenopus ATL. The sample also contained sperm chromatin to stabilize the network by reducing thermal convection. Scale bars = 1 µm. (B) A mixture of interphase cytosol, light membranes, and an energy regenerating system was incubated in the presence of 0.5 µM cytATL-GFP, but absence of membrane stain,for 30 min (left panel). Parallel reactions were performed with 2 µM cytATL(R232Q)-GFP and the membrane stain octadecyl rhodamine (middle and right panels). Scale bars = 10 µm.