4bzk

The structure of the COPII coat assembled on membranes

spinqualitylabelsall models 4bzk, resolution 40.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4bzk is a 4 chain structure with sequence from Atcc 18824. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 4bzi, 4bzj Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SEC31_YEAST] Component of the coat protein complex II (COPII) which promotes the formation of transport vesicles from the endoplasmic reticulum (ER). The coat has two main functions, the physical deformation of the endoplasmic reticulum membrane into vesicles and the selection of cargo molecules. [SEC13_YEAST] Functions as a component of the nuclear pore complex (NPC) and the COPII coat. It is one of 5 proteins constituting the COPII coat, which is involved in anterograde (ER to Golgi) double-membrane transport vesicle formation. First the small GTPase SAR1, activated by and binding to the integral ER membrane protein SEC12, exchanges GDP for GTP and recruits the heterodimer SEC23/24, which in turn recruits the heterotetramer SEC13-SEC31. The polymerization of COPII coat complexes then causes physically the deformation (budding) of the membrane, leading to the creation of a transport vesicle. The COPII complex is dissociated upon SAR1-GTP hydrolysis to SAR1-GDP. SEC23 functions as the SAR1 GTPase activating protein, whose activity is stimulated in the presence of SEC13/31. SEC13 is directly or indirectly required for normal ER membrane and nuclear envelope morphology. It also functions as a component of the nuclear pore complex (NPC). NPC components, collectively referred to as nucleoporins (NUPs), can play the role of both NPC structural components and of docking or interaction partners for transiently associated nuclear transport factors. SEC13 is required for efficient mRNA export from the nucleus to the cytoplasm and for correct nuclear pore biogenesis and distribution. Component of the SEA complex which coats the vacuolar membrane and is involved in intracellular trafficking, autophagy, response to nitrogen starvation, and amino acid biogenesis. Publication Abstract from PubMed Coat protein complex II (COPII) mediates formation of the membrane vesicles that export newly synthesised proteins from the endoplasmic reticulum. The inner COPII proteins bind to cargo and membrane, linking them to the outer COPII components that form a cage around the vesicle. Regulated flexibility in coat architecture is essential for transport of a variety of differently sized cargoes, but structural data on the assembled coat has not been available. We have used cryo-electron tomography and subtomogram averaging to determine the structure of the complete, membrane-assembled COPII coat. We describe a novel arrangement of the outer coat and find that the inner coat can assemble into regular lattices. The data reveal how coat subunits interact with one another and with the membrane, suggesting how coordinated assembly of inner and outer coats can mediate and regulate packaging of vesicles ranging from small spheres to large tubular carriers. DOI:https://dx.doi.org/10.7554/eLife.00951.001. The structure of the COPII transport-vesicle coat assembled on membranes.,Zanetti G, Prinz S, Daum S, Meister A, Schekman R, Bacia K, Briggs JA Elife. 2013 Sep 17;2:e00951. doi: 10.7554/eLife.00951. PMID:24062940 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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