Figure 3.

Scavenger receptor class B type I (SR-BI) localisation in coated pits during the early phase of lipid absorption. (A) Electron micrograph of the brush border region of an enterocyte of an explant, cultured for 30 minutes in the presence of lipid, as described in the methods section. Many coated pits (CP) are present between adjacent microvilli (MM) in the terminal web region. (B) Immunogold labelling of an ultracryosection for clathrin, showing labelling of an apical coated pit (CP) and a coated vesicle (CV). (C, D) Double immunogold labelling of ultracryosections for SR-BI (5 nm particles, indicated by arrowheads) and clathrin (10 nm particles, indicated by arrows), showing colocalisation in coated pits at the apical surface. Bars 0.5 μm (A); 0.2 μm (B–D).