Abstract
Junctional adhesion molecules (JAMs) are cell surface adhesion receptors of the immunoglobulin superfamily. JAMs are involved in a variety of biological processes both in the adult organism but also during development. These include processes such as inflammation, angiogenesis, hemostasis, or epithelial barrier formation, but also developmental processes such as hematopoiesis, germ cell development, and development of the nervous system. Several of these functions of JAMs depend on a physical and functional interaction with integrins. The JAM – integrin interactions in trans regulate cell-cell adhesion, their interactions in cis regulate signaling processes originating at the cell surface. The JAM – integrin interaction can regulate the function of the JAM as well as the function of the integrin. Beyond the physical interaction with integrins, JAMs can regulate integrin function through intracellular signaling indicating an additional level of JAM – integrin cross-talk. In this review, we describe the various levels of the functional interplay between JAMs and integrins and the role of this interplay during different physiological processes.
Highlights
Junctional adhesion molecules (JAMs) belong to the immunoglobulin superfamily (IgSF) of cell adhesion receptors
Since recent evidence suggests a role of JAM-A monomers in endothelial signaling through cis-heterophilic interactions with tetraspanins and integrins [39], any changes in the state of dimerization could result in altered endothelial signaling, which is required for the opening of endothelial cell-cell contacts during leukocyte extravasation [40]
A similar mechanism has been described for leukocyte-specific JAML, which is retained in a complex with α4β1 integrin as adhesion-incompetent monomer, and which is released from this complex upon integrin activation to undergo cis-dimerization followed by trans-heterophilic interaction with coxsackie and adenovirus receptor (CAR) [59]
Summary
Junctional adhesion molecules (JAMs) belong to the immunoglobulin superfamily (IgSF) of cell adhesion receptors. JAMs can undergo heterophilic interactions, and these interactions can occur both in cis and in trans [18]. Cis interactions are referred to as lateral associations with other integral membrane proteins expressed by the same cell, which can be mediated by the extracellular domains or by the cytoplasmic domains of the partners. Trans interactions are referred to as interactions which involve the extracellular domains of two proteins that are expressed by two different cells [19,20]. More recent findings revealed members of the integrin superfamily as major partners of JAM heterophilic interactions in both cis and trans. The adhesive activity of integrins is regulatable by cell surface receptor-initiated signals which trigger a switch from an inactive to an active conformation able to interact with ligands [21,23]. Article, we summarize the recent observations which indicate a mutual functional regulation of JAMs and integrins
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
