Contact

Prof. Dr. Michael Krauß
phone +49 30 94793 - 368 (lab)
krauss(at)fmp-berlin.de

Research Krauß Lab

Phosphoinositides as Spatial Landmarks for Membrane Translocation of Adaptor Proteins

Adaptor proteins are essential to promote the incorporation of cargo proteins into newly forming transport vesicles. A plethora of different adaptor proteins have been identified to date; most of them contribute unique functions in individual transport events. Many adaptor proteins therefore selectively associate with distinct intracellular membrane surfaces. This specificity is greatly supported by a variety of phosphoinositides, derivatives of the membrane phospholipid phosphatidylinositol, which can be (de-)phosphorylated at various positions of the inositol ring. Phosphoinositides usually serve as spatiotemporal landmarks to coordinate the membrane translocation of cytosolic proteins that harbor appropriate PI-recognizing domains. AP-2 for instance, a heterotetrameric adaptor complex mediating endocytosis of a large variety of ligands, harbours two binding sites for PI(4,5)P2, a PI species that is predominantly synthesized at the plasma membrane. Depletion of plasmalemmal PI(4,5)P2 can be achieved by overexpression of a membrane targeted 5-phosphatase domain.

 

Overexpression of the 5-phosphatase domain of synaptojanin, the major PI(4,5)P2-metabolizing enzyme in neurons, triggers the mislocalization of AP-2 and concomitantly completely abolishes the internalization of AP-2-dependent cargo proteins, as for instance the transferring receptor (Krauss et al., 2003).

Leibniz-Forschungsinstitut für Molekulare Pharmakologie im Forschungsverbund Berlin e.V. (FMP)
Campus Berlin-Buch
Robert-Roessle-Str. 10
13125 Berlin, Germany
+4930 94793 - 100 
+4930 94793 - 109 (Fax)
info(at)fmp-berlin.de

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