Structure and Organization of Coat Proteins in the COPll Cage

Journal Article · Mon Jan 01 04:00:00 EST 2007 · Cell

DOI:https://doi.org/10.1016/j.cell.2007.05.036· OSTI ID:930476

Fath, S; Mancias, J; Bi, X; Goldberg, J

COPII-coated vesicles export newly synthesized proteins from the endoplasmic reticulum. The COPII coat consists of the Sec23/24-Sar1 complex that selects cargo and the Sec13/31 assembly unit that can polymerize into an octahedral cage and deform the membrane into a bud. Crystallographic analysis of the assembly unit reveals a 28 nm long rod comprising a central {alpha}-solenoid dimer capped by two {beta}-propeller domains at each end. We construct a molecular model of the COPII cage by fitting Sec13/31 crystal structures into a recently determined electron microscopy density map. The vertex geometry involves four copies of the Sec31 {beta}-propeller that converge through their axial ends; there is no interdigitation of assembly units of the kind seen in clathrin cages. We also propose that the assembly unit has a central hinge -- an arrangement of interlocked {alpha}-solenoids -- about which it can bend to adapt to cages of variable curvature.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 930476
• Report Number(s): BNL--81228-2008-JA
• Journal Information: Cell, Journal Name: Cell Journal Issue: 7 Vol. 129; ISSN 0092-8674; ISSN CELLB5
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARGO
CRYSTAL STRUCTURE
DIMERS
ELECTRON MICROSCOPY
ENDOPLASMIC RETICULUM
EXPORTS
GEOMETRY
MEMBRANES
MOLECULAR MODELS
PROTEINS
national synchrotron light source