Cadherin interaction probed by atomic force microscopy
AUTOR(ES)
Baumgartner, W.
FONTE
The National Academy of Sciences
RESUMO
Single molecule atomic force microscopy was used to characterize structure, binding strength (unbinding force), and binding kinetics of a classical cadherin, vascular endothelial (VE)-cadherin, secreted by transfected Chinese hamster ovary cells as cis-dimerized full-length external domain fused to Fc-portion of human IgG. In physiological buffer, the external domain of VE-cadherin dimers is a ≈20-nm-long rod-shaped molecule that collapses and dissociates into monomers (V-shaped structures) in the absence of Ca2+. Trans-interaction of dimers is a low-affinity reaction (KD = 10−3–10−5 M, koff = 1.8 s−1, kon = 103–105 M−1·s−1) with relatively low unbinding force (35–55 pN at retrace velocities of 200–4,000 nm·s−1). Higher order unbinding forces, that increase with interaction time, indicate association of cadherins into complexes with cumulative binding strength. These observations favor a model by which the inherently weak unit binding strength and affinity of cadherin trans-interaction requires clustering and cytoskeletal immobilization for amplification. Binding is regulated by low-affinity Ca2+ binding sites (KD = 1.15 mM) with high cooperativity (Hill coefficient of 5.04). Local changes of free extracellular Ca2+ in the narrow intercellular space may be of physiological importance to facilitate rapid remodeling of intercellular adhesion and communication.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=18132Documentos Relacionados
- Stiffness Tomography by Atomic Force Microscopy
- The relationship between ligand-binding thermodynamics and protein-ligand interaction forces measured by atomic force microscopy.
- Visualization of RNA crystal growth by atomic force microscopy.
- Visualization of plant cell walls by atomic force microscopy.
- Molecular determinants of bacterial adhesion monitored by atomic force microscopy
