3ml6
a complex between Dishevelled2 and clathrin adaptor AP-2
Structural highlights
FunctionDVL2_MOUSE Participates in Wnt signaling by binding to the cytoplasmic C-terminus of frizzled family members and transducing the Wnt signal to down-stream effectors. Promotes internalization and degradation of frizzled proteins upon Wnt signaling. Plays a role both in canonical and non-canonical Wnt signaling. Plays a role in the signal transduction pathways mediated by multiple Wnt genes.[1] [2] [3] AP2M1_RAT Component of the adaptor protein complex 2 (AP-2). Adaptor protein complexes function in protein transport via transport vesicles in different membrane traffic pathways. Adaptor protein complexes are vesicle coat components and appear to be involved in cargo selection and vesicle formation. AP-2 is involved in clathrin-dependent endocytosis in which cargo proteins are incorporated into vesicles surrounded by clathrin (clathrin-coated vesicles, CCVs) which are destined for fusion with the early endosome. The clathrin lattice serves as a mechanical scaffold but is itself unable to bind directly to membrane components. Clathrin-associated adaptor protein (AP) complexes which can bind directly to both the clathrin lattice and to the lipid and protein components of membranes are considered to be the major clathrin adaptors contributing the CCV formation. AP-2 also serves as a cargo receptor to selectively sort the membrane proteins involved in receptor-mediated endocytosis. AP-2 seems to play a role in the recycling of synaptic vesicle membranes from the presynaptic surface. AP-2 recognizes Y-X-X-[FILMV] (Y-X-X-Phi) and [ED]-X-X-X-L-[LI] endocytosis signal motifs within the cytosolic tails of transmembrane cargo molecules. AP-2 may also play a role in maintaining normal post-endocytic trafficking through the ARF6-regulated, non-clathrin pathway. The AP-2 mu subunit binds to transmembrane cargo proteins; it recognizes the Y-X-X-Phi motifs. The surface region interacting with to the Y-X-X-Phi motif is inaccessible in cytosolic AP-2, but becomes accessible through a conformational change following phosphorylation of AP-2 mu subunit at 'Tyr-156' in membrane-associated AP-2. The membrane-specific phosphorylation event appears to involve assembled clathrin which activates the AP-2 mu kinase AAK1 (By similarity). Plays a role in endocytosis of frizzled family members upon Wnt signaling.[4] [5] [6] [7] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWnt association with its receptor, Frizzled (Fz), and recruitment by the latter of an adaptor, Dishevelled (Dvl), initiates signaling through at least two distinct pathways ("canonical" and "noncanonical"). Endocytosis and compartmentalization help determine the signaling outcome. Our previous work has shown that Dvl2 links at least one Frizzled family member (Fz4) to clathrin-mediated endocytosis by interacting with the mu2 subunit of the AP-2 clathrin adaptor, through both a classical endocytic tyrosine motif and a so-called "DEP domain." We report here the crystal structure of a chimeric protein that mimics the Dvl2-mu2 complex. The DEP domain binds at one end of the elongated, C-terminal domain of mu2. This domain:domain interface shows that parts of the mu2 surface distinct from the tyrosine-motif site can help recruit specific receptors or adaptors into a clathrin coated pit. Mutation of residues at the DEP-mu2 contact or in the tyrosine motif reduce affinity of Dvl2 for mu2 and block efficient internalization of Fz4 in response to ligation by Wnt5a. The crystal structure has thus allowed us to identify the specific interaction that leads to Frizzled uptake and to downstream, noncanonical signaling events. Structural analysis of the interaction between Dishevelled2 and clathrin AP-2 adaptor, a critical step in noncanonical Wnt signaling.,Yu A, Xing Y, Harrison SC, Kirchhausen T Structure. 2010 Oct 13;18(10):1311-20. PMID:20947020[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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