3zym
Structure of CALM (PICALM) in complex with VAMP8Structure of CALM (PICALM) in complex with VAMP8
Structural highlights
Function[PICA_RAT] Assembly protein recruiting clathrin and adaptor protein complex 2 (AP2) to cell membranes at sites of coated-pit formation and clathrin-vesicle assembly. May be required to determine the amount of membrane to be recycled, possibly by regulating the size of the clathrin cage. Involved in AP2-dependent clathrin-mediated endocytosis at the neuromuscular junction (By similarity).[UniProtKB:Q13492] Publication Abstract from PubMedSNAREs provide a large part of the specificity and energy needed for membrane fusion and, to do so, must be localized to their correct membranes. Here, we show that the R-SNAREs VAMP8, VAMP3, and VAMP2, which cycle between the plasma membrane and endosomes, bind directly to the ubiquitously expressed, PtdIns4,5P(2)-binding, endocytic clathrin adaptor CALM/PICALM. X-ray crystallography shows that the N-terminal halves of their SNARE motifs bind the CALM(ANTH) domain as helices in a manner that mimics SNARE complex formation. Mutation of residues in the CALM:SNARE interface inhibits binding in vitro and prevents R-SNARE endocytosis in vivo. Thus, CALM:R-SNARE interactions ensure that R-SNAREs, required for the fusion of endocytic clathrin-coated vesicles with endosomes and also for subsequent postendosomal trafficking, are sorted into endocytic vesicles. CALM's role in directing the endocytosis of small R-SNAREs may provide insight into the association of CALM/PICALM mutations with growth retardation, cognitive defects, and Alzheimer's disease. The Molecular Basis for the Endocytosis of Small R-SNAREs by the Clathrin Adaptor CALM.,Miller SE, Sahlender DA, Graham SC, Honing S, Robinson MS, Peden AA, Owen DJ Cell. 2011 Nov 23;147(5):1118-31. PMID:22118466[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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