Figure 11.

Cntn-2 mediates homophilic but not heterophilic adhesion. a, b, K562 cells stably expressing cntn2 were fluorescently labeled, dissociated mechanically, and agitated gently for 1 h. Nontransfected cell remained isolated, but Cntn2-expressing cells aggregated. c–j, Stably transfected K562 cells were dissociated mechanically and stained, then two populations stained with contrasting fluorophores and agitated for 1 h to promote aggregation. Cntn-2, Cntn-4, Sdk-1, Sdk-2, Dscam, and DscamL promoted homophilic aggregation, while Cntn-3-expressing cells aggregated poorly under these conditions. Cells expressing Cntn2 did not aggregate detectably with cells expressing any of the other IgSF genes tested. Thus, cntn2 promotes homophilic but not heterophilic adhesion. f–h are composites, showing two clusters that were from the same well but were not adjacent. k–m, Histograms show percentage of red cells in aggregates from Cntn2-green/Cntn2-red (k), Cntn4-green/Cntn4-red (l), or Cntn-2-green/Cntn4-red (m) combinations. These results confirm that Cntn2 and Cntn4 each support homophilic but not heterophilic adhesion. Scale bar: 5 μm for a, b; 10 μm for c–j.