6gni

Cryo-tomography and subtomogram averaging of Sar1-Sec23-Sec24 - fitted model.

Loading... Status: waiting for Mol* initialization Structural highlights 6gni is a 3 chain structure with sequence from Baker's yeast. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GNP, MG, ZN Gene: SEC23, YPR181C, P9705.14 (Baker's yeast), SEC24, ANU1, YIL109C (Baker's yeast), SAR1, YPL218W (Baker's yeast) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SEC23_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. SEC23 interacts with BET3 in order to target TRAPPI complex to COPII involved in internalisation of plasma membrane proteins like the maltose transporter. [SAR1_YEAST] Small GTPase 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. SAR1 controls the coat assembly in a stepwise manner. Activated SAR1-GTP by SEC12 binds to membranes first and recruits the SEC23/24 complex. These SEC23/24-SAR1 prebudding intermediates are then collected by the SEC13/31 complex as subunits polymerize to form coated transport vesicles. Conversion to SAR1-GDP triggers coat release and recycles COPII subunits. [SEC24_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. SEC24 specifically recruits cargo proteins like BET1 or SYS1 to the COPII vesicles. The SEC23/24 complex is also involved in internalisation of plasma membrane proteins like the maltose transporter. Publication Abstract from PubMed Eukaryotic cells employ membrane-bound carriers to transport cargo between compartments in a process essential to cell functionality. Carriers are generated by coat complexes that couple cargo capture to membrane deformation. The COPII coat mediates export from the endoplasmic reticulum by assembling in inner and outer layers, yielding carriers of variable shape and size that allow secretion of thousands of diverse cargo. Despite detailed understanding of COPII subunits, the molecular mechanisms of coat assembly and membrane deformation are unclear. Here we present a 4.9 A cryo-tomography subtomogram averaging structure of in vitro-reconstituted membrane-bound inner coat. We show that the outer coat (Sec13-Sec31) bridges inner coat subunits (Sar1-Sec23-Sec24), promoting their assembly into a tight lattice. We directly visualize the membrane-embedded Sar1 amphipathic helix, revealing that lattice formation induces parallel helix insertions, yielding tubular curvature. We propose that regulators like the procollagen receptor TANGO1 modulate this mechanism to determine vesicle shape and size. Subtomogram averaging of COPII assemblies reveals how coat organization dictates membrane shape.,Hutchings J, Stancheva V, Miller EA, Zanetti G Nat Commun. 2018 Oct 8;9(1):4154. doi: 10.1038/s41467-018-06577-4. PMID:30297805 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also GTP-binding protein 3D structures

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