ARF1 is directly involved in dynamin-independent endocytosis

S Kumari, S Mayor - Nature cell biology, 2008 - nature.com
Nature cell biology, 2008nature.com
Endocytosis of glycosylphosphatidyl inositol (GPI)-anchored proteins (GPI-APs) and the fluid
phase takes place primarily through a dynamin-and clathrin-independent, Cdc42-regulated
pinocytic mechanism. This mechanism is mediated by primary carriers called clathrin-
independent carriers (CLICs), which fuse to form tubular early endocytic compartments
called GPI-AP enriched endosomal compartments (GEECs). Here, we show that reduction in
activity or levels of ARF1 specifically inhibits GPI-AP and fluid-phase endocytosis without …
Abstract
Endocytosis of glycosylphosphatidyl inositol (GPI)-anchored proteins (GPI-APs) and the fluid phase takes place primarily through a dynamin- and clathrin-independent, Cdc42-regulated pinocytic mechanism. This mechanism is mediated by primary carriers called clathrin-independent carriers (CLICs), which fuse to form tubular early endocytic compartments called GPI-AP enriched endosomal compartments (GEECs). Here, we show that reduction in activity or levels of ARF1 specifically inhibits GPI-AP and fluid-phase endocytosis without affecting other clathrin-dependent or independent endocytic pathways. ARF1 is activated at distinct sites on the plasma membrane, and by the recruitment of RhoGAP domain-containing protein, ARHGAP10, to the plasma membrane, modulates cell-surface Cdc42 dynamics. This results in the coupling of ARF1 and Cdc42 activity to regulate endocytosis at the plasma membrane. These findings provide a molecular basis for a crosstalk of endocytosis with secretion by the sharing of a key regulator of secretory traffic, ARF1.
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