Fig. 3.

The CTPD domain leads to transient degradation and labelling of extracellular vesicles. a An mCherry and CTPD-tagged PH reporter localizes to the plasma membrane in one-cell embryos, but begins to be degraded during mitosis. Weaker fluorescence persists in embryonic cells from the two-cell stage on, but polar bodies remain brightly labelled (arrowhead, n = 42). Scale bar: 10 µm. b After tat-5 knockdown, the mCh::PH::CTPD reporter still degrades, but bright patches of extracellular vesicles are visible in the eggshell, floating around the embryo, and on the embryo surface, in addition to the brightly labelled polar bodies (arrowhead, n = 43). See also Supplementary Movie 2. c Loss of mCh::PH::CTPD fluorescence from the cell surface begins ~3 min before cytokinetic furrow ingression, but degradation tapers off leaving residual mCh::PH::CTPD fluorescence after the two-cell stage. Fluorescence intensity was normalized to the first polar body to correct for photobleaching. Bars represent mean ± s.e.m. (n = 5–12). Source data are provided as a Source Data file. d Phosphorylation of the CTPD degrons leads to recognition of the CTPD by multiple SCF ubiquitin ligases, ubiquitination, and degradation