CIE and CDE pathways showing lipid content and regulatory molecules

Schematic illustration of CIE and CDE pathways showing lipid content and regulatory molecules. Constitutive CIE vesicles contain cargo such as MHCI (blue bars) while CDE vesicles contain cargo such as transferrin receptor (green bars). CIE vesicles lose PIP2 and may acquire Rab5 prior to fusion with Rab5, EEA1-positive, “classical” early endosome (EE) containing CDE cargo. From here, CIE cargo may go on to late endosomes (LE) and lysosomes for degradation. CIE cargo destined for recycling reaches the endosomal recycling compartment (ERC) either directly or after fusion with “classical” EE and is recycled back out to the PM via tubular membranes that do not contain CDE cargo. Recycling back out to the PM requires Rab22 and probably Rab8 for tubule formation and Rab11, Arf6, Par 3, Par6, Cdc42 and actin for fusion back to the PM. Activation of Arf6, Ras and Src leads to PM ruffling and macropinocytosis that alters the architecture of the CIE. Macropinosomes mature from PIP2/PIP3-containing by loss of PIP2, acquisition of Rab5 and loss of PIP3. The bulk of the macropinosome membrane is recycled back out to the PM using CIE pathway recycling components.

Publication

Clathrin-Independent Endocytosis: A unique Platform for Cell Signaling and PM Remodeling. () Julie G. Donaldson, et al. Cell Signal. ;21(1):1-6. Figure: F1. All organisms Drosophila melanogaster Homo sapiens

Disease mentions