In each domain of Ig, there are 70-110amino acid compositionA tightly folded structure.Later, in many different kinds ofproteinThe existence of Ig like domains is also found in, and these structures together with Ig antibodies constitute the immunoglobulins superfamily (IgSF). Most members of IgSF areIntegrin, exists inlymphocyteIt participates in various immune activities.Some of themIntegrinIt is involved in the adhesion between calcium independent cells.In fact, in the absence ofimmune systemOfinvertebrateCell adhesion moleculeThe Ig like domain was found in, indicating that Ig like proteins were used as cell adhesion mediators in the original evolution process, only latervertebrateHas been added to the immune systemimmunity。
IgSF adhesion protein molecules can mediate both homophilic cell adhesion and heterophilic cell adhesion, but most of them mediate homophilic cell adhesion.If homophilic cell adhesion is mediated, it is non Ca2+dependenceIf heterophilic cell adhesion is mediated, it is Ca2+dependent.IgSF protein on one cell can be the same or different IgSF protein on another cellprotein binding Mediates cell adhesion.For example, L1 molecules on one cell can bind to the same L1 molecules on another cell.In addition, IgSFSuperfamilyIt can also be achieved byIntegrinBinding mediates cell adhesion, as in somevascular endothelial cellIgSF protein onTarget cellIntegrin α 4 β 1 on the surface binds to mediate cell adhesion.
