Figure 10.

RE(AB)EGFP colocalizes with Raf-1 PA-sensor protein, whereas RE(AB)ΔCTR does not (confocal microscopy). Heterologously expressed full-length RIBEYE forms synaptic ribbon-like clusters in transfected COS cells (arrows, A–D, left) (Magupalli et al., 2008; Sheets et al., 2011). Full-length RIBEYE(AB)-EGFP generates PA as judged by the accumulation of the fluorescent PA-sensor protein Raf-1 at the ribbon-like RIBEYE clusters (A, B). The LPAAT-deficient RIBEYE(AB)ΔCTR, which lacks the CTR does not generate PA (Figs. 8D, 9) and therefore is also not able to accumulate the PA-sensor protein (C, D), although formation of artificial ribbons is not inhibited by the deletion (arrows; C, D; left). In contrast to the RIBEYE clusters formed by the wild-type protein (A, B), PA-sensor proteins were not enriched at RIBEYE clusters formed by the LPAAT-deficient RIBEYE(AB)ΔCTR (C, D). n, Nucleus. Scale bars: 10 μm.