Intercellular Junction Markers

Intercellular junctions are multiprotein structures that link neighboring cells and are crucial for maintaining multicellularity. These structures not only play a mechanical role by physically connecting cells within tissues and organs but also mediate intercellular communication by enabling the transport of ions and small molecules between connected cells. Tissues in vertebrates contain three main types of junctions, which are distinguished based on their composition and function: anchoring junctions, gap junctions, and tight junctions. The anchoring junction family can be further subdivided into adherens junctions and desmosomes. Invertebrates and other organisms also contain intercellular junctions, such as septate junctions in C. elegans and plasmodesmata in plants. The core structure of adherens junctions (AJs) is comprised of the cadherin-catenin protein complex. Additional interaction partners in the cytoplasm, including cytoskeletal components, modulate the structure and function of these adhesions. Calcium-dependent cadherin family members are transmembrane proteins expressed in a variety of tissues and include E-cadherin, N-cadherin, VE-cadherin, and P-cadherin. Through their extensions into the intermembrane space, cadherins enable intercellular connection through homophilic and/or heterophilic interactions. At their cytoplasmic face, cadherins bind directly to specific members of the catenin family, including β-catenin and p120. Interactions between β-catenin and α-catenin mediate coupling between AJs and the actin cytoskeleton. Many additional cytoplasmic partners are recruited to AJs in the cytoplasm to regulate downstream signaling pathways. Strikingly, AJs are mechanosensitive – force applied through the actin cytoskeleton can modulate the structure and function of AJs. For example, α-catenin undergoes a conformational change in response to the application of force that enables the recruitment of vinculin and strengthening of the AJ-actin linkage. Desmosomes are found primarily in epithelial tissues and the heart. Like AJs, their core structure contains cadherin family proteins, the desmogleins and desmocollins, which show tissue-specific expression patterns. In the cytoplasm, desmosomal cadherins interact with plakoglobin and plakophilin. These proteins recruit desmoplakin, which mediates the interaction between desmosomes and the intermediate filament cytoskeleton, including keratins. Desmosomes are especially crucial for maintaining the mechanical integrity of the epidermis and cardiac tissue. Consequently, mutations in desmosomal components are linked to diseases of the skin and heart. Gap junctions are intercellular channels that enable the diffusion of ions and small molecules between cells. They are composed of connexins, a large family of transmembrane proteins that are named based on their molecular weight (for example, Cx43). In humans, 21 connexin family members have been identified. Notably, gap junctions facilitate the electrical coupling of cells in the heart, enabling coordinated cardiomyocyte contraction, and in the brain at electrical synapses. Tight junctions are unique to vertebrates and are found in epithelial and endothelial tissues. They mediate barrier formation by regulating the paracellular transport of ions and solutes. In polarized epithelia, tight junctions also define the borders between the apical and basolateral domains. They are composed of transmembrane claudins, occludins, and junctional adhesion molecules (JAMs). These components interact with a variety of cytoplasmic partners, including ZO-1, which enables interaction between tight junctions and the actin cytoskeleton. The permeability of tight junctions is defined by their claudin composition, of which over two dozen members have been identified. We offer a broad range of intercellular junction markers including beta Catenin antibodies, CD31 antibodies, Desmoglein 3 antibodies, and N Cadherin antibodies, covering various host species, antibody types, applications, and conjugates.