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J Cell Sci. 2016 Aug 15;129(16):3077-83. doi: 10.1242/jcs.191262. Epub 2016 Jul 1.

Architecture of the caveolar coat complex.

Author information

1
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore aludwig@ntu.edu.sg.
2
MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
3
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore NTU Institute of Structural Biology, Nanyang Technological University, Experimental Medicine Building, 59 Nanyang Drive, 637551 Singapore.

Abstract

Caveolae are specialized membrane domains that are crucial for the correct function of endothelial cells, adipocytes and muscle cells. Caveolins and cavins are both required for caveolae formation, and assemble into a large (80S) caveolar coat complex (80S-CCC). The architecture of the 80S-CCC, however, has not been analyzed. Here, we study the 80S-CCC isolated from mammalian cells using negative stain electron microscopy and 3D cryo-electron tomography. We show that the 80S-CCC is a hollow sphere with a diameter of 50-80 nm, and so has the same size and shape as individual caveolar bulbs. This provides strong evidence that the distinctive membrane shape of caveolae is generated by the shape of the 80S-CCC itself. The particle appears to be made up of two layers, an inner coat composed of polygonal units of caveolins that form a polyhedral cage, and an outer filamentous coat composed of cavins. The data suggest that the peripheral cavin coat is aligned along the edges of the inner polyhedral cage, thereby providing a mechanism for the generation of a morphologically stable caveolar coat.

KEYWORDS:

Caveolae; Caveolar coat; Caveolin; Cavin; Cryo-electron tomography

PMID:
27369768
PMCID:
PMC5004899
DOI:
10.1242/jcs.191262
[Indexed for MEDLINE]
Free PMC Article

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