Homoassociation of VE-cadherin follows a mechanism common to "classical" cadherins.
Vascular endothelial cadherin (VE-cadherin/cadherin5) is specifically expressed in adherens junctions of endothelial cells and exerts important functions in cell-cell adhesion as well as signal transduction. To analyze the mechanism of VE-cadherin homoassociation, the ectodomains CAD1-5 were connected by linker sequences to the N terminus of the coiled-coil domain of cartilage matrix protein (CMP). The chimera VECADCMP were expressed in mammalian cells. The trimeric coiled-coil domain leads to high intrinsic domain concentrations and multivalency promoting self-association. Ca(2+)-dependent homophilic association of VECADCMP was detected in solid phase assays and cross-linking experiments. A striking analogy to homoassociation of type I ("classical") cadherins like E, N or P-cadherin was observed when interactions in VECADCMP and between these trimeric proteins were analyzed by electron microscopy. Ca(2+)-dependent ring-like and double ring-like arrangements suggest interactions between domains 1 and 2 of the ectodomains, which may be correlated with lateral and adhesive contacts in the adhesion process. Association to complexes composed of two VECADCMP molecules was also demonstrated by chemical cross-linking. No indication for an antiparallel association of VECAD ectodomains to hexameric complexes as proposed by Legrand et al. was found. Instead the data suggest that homoassociation of VE-cadherin follows the conserved mechanism of type I cadherins.
Ahrens
Thomas
T
Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
Lambert
Mireille
M
Pertz
Olivier
O
Sasaki
Takako
T
Schulthess
Therese
T
Mège
René-Marc
RM
Timpl
Rupert
R
Engel
Jürgen
J
D000818:Animals; D015703:Antigens, CD; D001483:Base Sequence; D015820:Cadherins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D002118:Calcium / Q000737:chemistry; D002448:Cell Adhesion; D002460:Cell Line; D002645:Chickens; D003432:Cross-Linking Reagents; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D051379:Mice; D008854:Microscopy, Electron; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D000099152:Cadherin 5
D015703:Antigens, CD; D015820:Cadherins; D002118:Calcium; D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D000099152:Cadherin 5