6ba6

<StructureSection load='6ba6' size='340' side='right' caption='[[6ba6]], [[NMR_Ensembles_of_Models | 20 NMR models]]' scene=''>

<table><tr><td colspan='2'>[[6ba6]] is a 2 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6BA6 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6BA6 FirstGlance]. <br>

</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6ba6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6ba6 OCA], [http://pdbe.org/6ba6 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6ba6 RCSB], [http://www.ebi.ac.uk/pdbsum/6ba6 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6ba6 ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/TLN1_MOUSE TLN1_MOUSE]] Probably involved in connections of major cytoskeletal structures to the plasma membrane. High molecular weight cytoskeletal protein concentrated at regions of cell-substratum contact and, in lymphocytes, at cell-cell contacts. [[http://www.uniprot.org/uniprot/RAP1B_HUMAN RAP1B_HUMAN]] GTP-binding protein that possesses intrinsic GTPase activity. Contributes to the polarizing activity of KRIT1 and CDH5 in the establishment and maintenance of correct endothelial cell polarity and vascular lumen. Required for the localization of phosphorylated PRKCZ, PARD3 and TIAM1 to the cell junction.<ref>PMID:20332120</ref> <ref>PMID:18660803</ref>

Activation of transmembrane receptor integrin by talin is essential for inducing cell adhesion. However, the pathway that recruits talin to the membrane, which critically controls talin's action, remains elusive. Membrane-anchored mammalian small GTPase Rap1 is known to bind talin-F0 domain but the binding was shown to be weak and thus hardly studied. Here we show structurally that talin-F0 binds to human Rap1b like canonical Rap1 effectors despite little sequence homology, and disruption of the binding strongly impairs integrin activation, cell adhesion, and cell spreading. Furthermore, while being weak in conventional binary binding conditions, the Rap1b/talin interaction becomes strong upon attachment of activated Rap1b to vesicular membranes that mimic the agonist-induced microenvironment. These data identify a crucial Rap1-mediated membrane-targeting mechanism for talin to activate integrin. They further broadly caution the analyses of weak protein-protein interactions that may be pivotal for function but neglected in the absence of specific cellular microenvironments.

 

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== References ==

[[Category: Qin, J]]

[[Category: Yang, J]]

[[Category: Zhu, L]]

[[Category: Cell adhesion]]

[[Category: Complex]]

[[Category: Small gtpase]]

[[Category: Ubiquitin-like fold]]