1xaw
From Proteopedia
(New page: 200px<br /> <applet load="1xaw" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xaw, resolution 1.45Å" /> '''crystal structure o...) |
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| - | [[Image:1xaw.gif|left|200px]]<br /> | + | [[Image:1xaw.gif|left|200px]]<br /><applet load="1xaw" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1xaw" size=" | + | |
caption="1xaw, resolution 1.45Å" /> | caption="1xaw, resolution 1.45Å" /> | ||
'''crystal structure of the cytoplasmic distal C-terminal domain of occludin'''<br /> | '''crystal structure of the cytoplasmic distal C-terminal domain of occludin'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Occludin is a transmembrane protein localized at tight junctions whose | + | Occludin is a transmembrane protein localized at tight junctions whose functions are complex yet poorly understood. Current evidence supports a role for occludin in both the formation of the paracellular barrier and in cell signaling. While the N-terminal extracellular domains of occludin mediate homotypic adhesion, the distal C-terminal cytoplasmic domain of occludin controls protein targeting and endocytosis. The C terminus can also bind to the scaffolding proteins ZO-1, ZO-2, ZO-3, cingulin, the membrane trafficking protein VAP33, and the cytoskeletal protein F-actin, suggesting an important role for this domain. This domain is highly homologous to an important functional domain in the C terminus of the ELL family of RNA polymerase II transcription factors. To explore the function of occludin, we determined the high-resolution crystal structure of its C-terminal distal cytoplasmic domain. The structure comprises three helices that form two separate anti-parallel coiled-coils and a loop that packs tightly against one of the coiled-coils. Using in vitro binding studies and site-directed mutagenesis, we have identified a large positively charged surface that contains the binding site for ZO-1, and this surface is required for proper localization of occludin to cell-cell junctions. On the basis of sequence conservation, we predict that occludin domains from different species and the C-terminal domain of the ELL transcription factors share a very similar structure. Our results provide a model to further test the function of occludin and its binding to other proteins. |
==About this Structure== | ==About this Structure== | ||
| - | 1XAW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http:// | + | 1XAW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XAW OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Anderson, J | + | [[Category: Anderson, J M.]] |
| - | [[Category: Fanning, A | + | [[Category: Fanning, A S.]] |
[[Category: Lavie, A.]] | [[Category: Lavie, A.]] | ||
[[Category: Li, Y.]] | [[Category: Li, Y.]] | ||
[[Category: coiled-coil]] | [[Category: coiled-coil]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:52:52 2008'' |
Revision as of 13:52, 21 February 2008
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crystal structure of the cytoplasmic distal C-terminal domain of occludin
Overview
Occludin is a transmembrane protein localized at tight junctions whose functions are complex yet poorly understood. Current evidence supports a role for occludin in both the formation of the paracellular barrier and in cell signaling. While the N-terminal extracellular domains of occludin mediate homotypic adhesion, the distal C-terminal cytoplasmic domain of occludin controls protein targeting and endocytosis. The C terminus can also bind to the scaffolding proteins ZO-1, ZO-2, ZO-3, cingulin, the membrane trafficking protein VAP33, and the cytoskeletal protein F-actin, suggesting an important role for this domain. This domain is highly homologous to an important functional domain in the C terminus of the ELL family of RNA polymerase II transcription factors. To explore the function of occludin, we determined the high-resolution crystal structure of its C-terminal distal cytoplasmic domain. The structure comprises three helices that form two separate anti-parallel coiled-coils and a loop that packs tightly against one of the coiled-coils. Using in vitro binding studies and site-directed mutagenesis, we have identified a large positively charged surface that contains the binding site for ZO-1, and this surface is required for proper localization of occludin to cell-cell junctions. On the basis of sequence conservation, we predict that occludin domains from different species and the C-terminal domain of the ELL transcription factors share a very similar structure. Our results provide a model to further test the function of occludin and its binding to other proteins.
About this Structure
1XAW is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structure of the conserved cytoplasmic C-terminal domain of occludin: identification of the ZO-1 binding surface., Li Y, Fanning AS, Anderson JM, Lavie A, J Mol Biol. 2005 Sep 9;352(1):151-64. PMID:16081103
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