Membrane-trafficking sorting hubs: Cooperation between PI4P and small GTPases at the trans-Golgi network

Department of Molecular Biology and Genetics, 107 Biotechnology Bldg., Cornell University, Ithaca, NY 14853-7202, USA.
Trends in cell biology (Impact Factor: 12.01). 07/2011; 21(9):515-25. DOI: 10.1016/j.tcb.2011.05.005
Source: PubMed


Cell polarity in eukaryotes requires constant sorting, packaging and transport of membrane-bound cargo within the cell. These processes occur in two sorting hubs: the recycling endosome for incoming material and the trans-Golgi network for outgoing material. Phosphatidylinositol 3-phosphate and phosphatidylinositol 4-phosphate are enriched at the endocytic and exocytic sorting hubs, respectively, where they act together with small GTPases to recruit factors to segregate cargo and regulate carrier formation and transport. In this review, we summarize the current understanding of how these lipids and GTPases regulate membrane trafficking directly, emphasizing the recent discoveries of phosphatidylinositol 4-phosphate functions at the trans-Golgi network.

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Available from: Felipe H Santiago-Tirado, Apr 30, 2014
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    • "They are composed of a phosphatidylinositol kinase, effector proteins that specifically recognize its product, and a phosphatase that terminates signaling. The phosphatidylinositol 4-phosphate (PtdIns4P) signaling modules that function at the Golgi apparatus control the lipid content of Golgi membranes and regulate export of cargo from the trans-Golgi network (TGN; Graham and Burd, 2011; Santiago-Tirado and Bretscher, 2011). PtdIns4P is largely restricted to the TGN and, hence, this lipid is a defining feature of this compartment. "
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    • "PI4P is enriched in the TGN and recruits four-phosphate-adaptor protein (FAPP) 1 and FAPP2, which bind the small GTPase [ADP-ribosylation factor (Arf )] Arf1- guanidine triphosphate (GTP). Through interaction of the pleckstrin homology (PH) domain of FAPPs with PI4P and Arf1-GTP, vesicle formation and transport of cargo to the PM is regulated (Godi et al., 2004; Santiago-Tirado and Bretscher, 2011). Phosphoinositol kinases are differentially localized in the Golgi complex to control local production of PI4P. "
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