Role of each immunoglobulin-like loop of nectin for its cell-cell adhesion activity.
Nectins are Ca(2+)-independent immunoglobulin (Ig)-like cell-cell adhesion molecules that form cell-cell junctions, cooperatively with or independently of cadherins, in a variety of cells. Nectins comprise a family of four members, nectin-1, -2, -3, and -4. All nectins have one extracellular region with three Ig-like loops, one transmembrane segment, and one cytoplasmic tail. It has been shown mainly by use of cadherin-deficient L fibroblasts stably expressing each nectin that nectins first form homo-cis-dimers and then homo- or hetero-trans-dimers, causing cell-cell adhesion, and that the formation of the cis-dimers is necessary for the formation of the trans-dimers. However, kinetics of the formation of these dimers have not been examined biochemically by use of pure nectin proteins. We prepared here pure recombinant proteins of extracellular fragments of nectin-3 containing various combinations of Ig-like loops, all of which were fused to the Fc portion of IgG and formed homo-cis-dimers through the Fc portion, and of an extracellular fragment of nectin-1 containing three Ig-like loops which was fused to secreted alkaline phosphatase and formed homo-cis-dimers. We showed here by use of these proteins that the first Ig-like loop of nectin-3 was essential and sufficient for the formation of trans-dimers with nectin-1, but that the second Ig-like loop of nectin-3 was furthermore necessary for its cell-cell adhesion activity.
Yasumi
Masato
M
Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita 565-0871, Osaka, Japan.
Shimizu
Kazuya
K
Honda
Tomoyuki
T
Takeuchi
Masakazu
M
Takai
Yoshimi
Y
D002448:Cell Adhesion / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000502:physiology*; D002460:Cell Line; D000075983:Nectins; D020349:Surface Plasmon Resonance
D015815:Cell Adhesion Molecules; D000075983:Nectins