Sandbox Reserved 1493: Difference between revisions
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It opens a hinge in the integrin which triggers a very quick succession of subunit shifts transmitted from the tail to the extracellular headpiece across the transmembrane domain ('''inside-out signaling'''). Movements of helices and loops move the headpiece to an '''extended conformation''' which uncovers the interface between the two subunits containing '''ligand binding sites'''. Integrin is at an '''intermediate affinity state''' (extended conformation, closed headpiece) and can bind ligands. | It opens a hinge in the integrin which triggers a very quick succession of subunit shifts transmitted from the tail to the extracellular headpiece across the transmembrane domain ('''inside-out signaling'''). Movements of helices and loops move the headpiece to an '''extended conformation''' which uncovers the interface between the two subunits containing '''ligand binding sites'''. Integrin is at an '''intermediate affinity state''' (extended conformation, closed headpiece) and can bind ligands. | ||
[[Image: | [[Image:Activation2.png|thumb|right|Activation of the binding site at intermediate affinity]] | ||
The precise mechanisms of activation which occur in the extracellular part of the integrin remain a mystery. Still, the conformational difference of a disulfide-bonded knot localised in the '''cysteine-rich core''' of the β3 subunit between inactivation and activation suggests that this region plays a part in activation. It is thought that the cysteine core of the β3 subunit linked to its N-terminal extremity apply a conformational constraint on the ligand binding site. It includes a few cysteines that remain unpaired and which redox state influence the activation of the integrin, which supposed this region could host a redox site. | The precise mechanisms of activation which occur in the extracellular part of the integrin remain a mystery. Still, the conformational difference of a disulfide-bonded knot localised in the '''cysteine-rich core''' of the β3 subunit between inactivation and activation suggests that this region plays a part in activation. It is thought that the cysteine core of the β3 subunit linked to its N-terminal extremity apply a conformational constraint on the ligand binding site. It includes a few cysteines that remain unpaired and which redox state influence the activation of the integrin, which supposed this region could host a redox site. | ||
