Prof. Dr. Michael Krauß
phone +49 30 94793 - 368 (lab)

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)

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