FIGURE 8.

Membrane disposition of MREG in ROS membranes and association of soluble MREG with PerCter. (A) Western blot analysis of untreated ROS membranes and ROS pellets and supernatants treated with HA as indicated. Blots were probed with anti-MREG mAb165. (B) PerCter interacts with soluble MREG. The GST-PerCter fusion protein attached to the glutathione resin was incubated with either the pellet or the supernatant fraction from HA-treated ROS. Samples were incubated at 4 °C overnight as detailed in Methods. Interaction of MREG and the purified PerCter was verified by Western blot analysis with anti-MREG mAb165. (C) Fusion was assessed as an increase in R₁₈ fluorescence over time as R₁₈PM was incubated with either untreated disk membranes (designated −HA), HA-treated disk membranes (designated +HA), disk membranes incubated with MREG containing HA supernatant (designated HA sup), or disk membranes preincubated with pure MREG (designated pure MREG). Fusion was assessed at 37 °C as described in detail in Methods. Data represent two independent experiments with fusion assays performed in triplicate.