Cell–Cell Junctions Organize Structural and Signaling Networks

Abstract

Cell-cell junctions link cells to each other in tissues, and regulate tissue homeostasis in critical cell processes that include tissue barrier function, cell proliferation and migration. Defects in cell-cell junctions give rise to a wide range of tissue abnormalities that disrupt homeostasis and are common in genetic abnormalities and cancers. Here, we discuss the organization and function of cell-cell junctions primarily involved in adhesion (Tight Junction, Adherens Junction, and Desmosomes) in two different epithelial tissues: a simple epithelium (intestine) and a stratified epithelium (epidermis). Studies in these tissues reveal similarities and differences in the organization and functions of different cell-cell junctions that meet the requirements for the specialized functions of each tissue. We discuss cell-cell junction responses to genetic and environmental perturbations that provide further insights into their roles in maintaining tissue homeostasis.

Developmental mechanisms driving complex tooth shape in reptiles

“…As we observed significant changes at the ultrastructural level of cellular membranes, we wanted to further analyze possible differences in membrane activity, which could be behind the process of cell rearrangement contributing to ridge formation. Na + /K + ‐ATPase is a transmembrane enzyme contributing to ion exchange and which may act as a signal transducer . We observed strong Na + /K + ‐ATPase expression in large cells located on the sides of the forming enamel ridge in chameleon (Figure A,B), especially in the mesial area (Figure A,A′).…”

Respiratory Barrier as a Safeguard and Regulator of Defense Against Influenza A Virus and Streptococcus pneumoniae

“…Three main transmembrane proteins [occludins, claudins, and junctional adhesion molecules (JAM)] are responsible for tightly sealing membranes of adjacent cells within the TJs. Peripheral membrane protein, zonula occludin (ZO), binds to these transmembrane proteins of the TJs to stabilize them in the cytoskeleton and mediate signaling (21)(22)(23). IAV infection disrupts the epithelial barrier by causing reduced expression of occludin, claudin-4, and JAM soon after infection (24).…”

“…The "one/united airway concept" was proposed to underscore the importance of considering changes that occur in the upper and lower airways concomitantly when investigating diseases that affect the respiratory tract like rhinitis and asthma (1). Approximately 2 23 branches lined with epithelial cells make up the airways (2) within the soft lung tissue that handles ∼10,000 L of inhaled air each day, placing this epithelial surface in contact with various noxious and innocuous material including environmentally disseminated viruses and bacteria. FIGURE 1 | The cellular composition of the upper and lower respiratory tracts that serves as the primary barrier.…”

Senescent HUVECs-secreted exosomes trigger endothelial barrier dysfunction in young endothelial cells

“…Beta-catenin links VE-cadherin junction complex to the cytoskeleton to maintain vascular endothelial cell-cell adhesions and barrier function. Cell-cell junctions regulate tissue homeostasis in cellular processes including cell growth and proliferation, and migration (Garcia et al, 2018[12]). Therefore, altered cell-cell junction formation affects signaling mediated through these junctional communications including cell growth and proliferation (Rodrigues and Granger, 2015[18]).…”