Molecular composition and ultrastructure of the caveolar coat complex.
Caveolae are an abundant feature of the plasma membrane of many mammalian cell types, and have key roles in mechano-transduction, metabolic regulation, and vascular permeability. Caveolin and cavin proteins, as well as EHD2 and pacsin 2, are all present in caveolae. How these proteins assemble to fo...
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Public Library of Science (PLoS)
2013-01-01
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| Series: | PLoS Biology |
| Online Access: | https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.1001640&type=printable |
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| author | Alexander Ludwig Gillian Howard Carolina Mendoza-Topaz Thomas Deerinck Mason Mackey Sara Sandin Mark H Ellisman Benjamin J Nichols |
| author_facet | Alexander Ludwig Gillian Howard Carolina Mendoza-Topaz Thomas Deerinck Mason Mackey Sara Sandin Mark H Ellisman Benjamin J Nichols |
| author_sort | Alexander Ludwig |
| collection | DOAJ |
| description | Caveolae are an abundant feature of the plasma membrane of many mammalian cell types, and have key roles in mechano-transduction, metabolic regulation, and vascular permeability. Caveolin and cavin proteins, as well as EHD2 and pacsin 2, are all present in caveolae. How these proteins assemble to form a protein interaction network for caveolar morphogenesis is not known. Using in vivo crosslinking, velocity gradient centrifugation, immuno-isolation, and tandem mass spectrometry, we determine that cavins and caveolins assemble into a homogenous 80S complex, which we term the caveolar coat complex. There are no further abundant components within this complex, and the complex excludes EHD2 and pacsin 2. Cavin 1 forms trimers and interacts with caveolin 1 with a molar ratio of about 1∶4. Cavins 2 and 3 compete for binding sites within the overall coat complex, and form distinct subcomplexes with cavin 1. The core interactions between caveolin 1 and cavin 1 are independent of cavin 2, cavin 3, and EHD2 expression, and the cavins themselves can still interact in the absence of caveolin 1. Using immuno-electron microscopy as well as a recently developed protein tag for electron microscopy (MiniSOG), we demonstrate that caveolar coat complexes form a distinct coat all around the caveolar bulb. In contrast, and consistent with our biochemical data, EHD2 defines a different domain at the caveolar neck. 3D electron tomograms of the caveolar coat, labeled using cavin-MiniSOG, show that the caveolar coat is composed of repeating units of a unitary caveolar coat complex. |
| format | Article |
| id | doaj-art-9466bd7b95cc4bbcbb34ce0705f121b0 |
| institution | Kabale University |
| issn | 1544-9173 1545-7885 |
| language | English |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Biology |
| spelling | doaj-art-9466bd7b95cc4bbcbb34ce0705f121b02025-08-20T03:46:12ZengPublic Library of Science (PLoS)PLoS Biology1544-91731545-78852013-01-01118e100164010.1371/journal.pbio.1001640Molecular composition and ultrastructure of the caveolar coat complex.Alexander LudwigGillian HowardCarolina Mendoza-TopazThomas DeerinckMason MackeySara SandinMark H EllismanBenjamin J NicholsCaveolae are an abundant feature of the plasma membrane of many mammalian cell types, and have key roles in mechano-transduction, metabolic regulation, and vascular permeability. Caveolin and cavin proteins, as well as EHD2 and pacsin 2, are all present in caveolae. How these proteins assemble to form a protein interaction network for caveolar morphogenesis is not known. Using in vivo crosslinking, velocity gradient centrifugation, immuno-isolation, and tandem mass spectrometry, we determine that cavins and caveolins assemble into a homogenous 80S complex, which we term the caveolar coat complex. There are no further abundant components within this complex, and the complex excludes EHD2 and pacsin 2. Cavin 1 forms trimers and interacts with caveolin 1 with a molar ratio of about 1∶4. Cavins 2 and 3 compete for binding sites within the overall coat complex, and form distinct subcomplexes with cavin 1. The core interactions between caveolin 1 and cavin 1 are independent of cavin 2, cavin 3, and EHD2 expression, and the cavins themselves can still interact in the absence of caveolin 1. Using immuno-electron microscopy as well as a recently developed protein tag for electron microscopy (MiniSOG), we demonstrate that caveolar coat complexes form a distinct coat all around the caveolar bulb. In contrast, and consistent with our biochemical data, EHD2 defines a different domain at the caveolar neck. 3D electron tomograms of the caveolar coat, labeled using cavin-MiniSOG, show that the caveolar coat is composed of repeating units of a unitary caveolar coat complex.https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.1001640&type=printable |
| spellingShingle | Alexander Ludwig Gillian Howard Carolina Mendoza-Topaz Thomas Deerinck Mason Mackey Sara Sandin Mark H Ellisman Benjamin J Nichols Molecular composition and ultrastructure of the caveolar coat complex. PLoS Biology |
| title | Molecular composition and ultrastructure of the caveolar coat complex. |
| title_full | Molecular composition and ultrastructure of the caveolar coat complex. |
| title_fullStr | Molecular composition and ultrastructure of the caveolar coat complex. |
| title_full_unstemmed | Molecular composition and ultrastructure of the caveolar coat complex. |
| title_short | Molecular composition and ultrastructure of the caveolar coat complex. |
| title_sort | molecular composition and ultrastructure of the caveolar coat complex |
| url | https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.1001640&type=printable |
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