Cell Junction & Cell Adhesion Antibodies
View our extensive references for cell junction antibodies.
Cell junctions regulate small-molecule trafficking between cells, organization of cells into tissues, and adherence of cells to each other and the extracellular matrix. There are five main types of cell junctions (Figure 1):
Dysfunctional junctions are implicated in several diseases, including cancer, neurodegeneration, and cardiovascular dysfunction. Understanding cell junctions is fundamental to understanding disease pathology.
|Figure 1—Five cellular junctions. Illustration shows gap junctions, tight junctions, adherens junctions, desmosome junction, and hemidesmosome junction.|
Gap junctions are clusters of tightly packed channels that allow small molecules (metabolites, second messengers, and ions) to travel between adjoining cells . This molecular exchange is essential during development and differentiation; it also creates cell proliferation, tumor suppression, cell death propagation, and survival-modulating signals . These signals include connexins, and pannexin 1 and 2, important components of synapses . Several kinases phosphorylate connexins and alter their functions:
- V-src kinase
- C-src kinase
- cdc2 kinase
- casein kinase I
A number of other proteins, such as ZO-1, ZO-2, β-catenin, drebrin, α/β tubulin, caveolin-1, NOV, CIP85, and OCP2 also associate with connexins. Connexin-43 (CX43) and connexin-40 work together to form cell junctions, essential for proper heart atrium cell function (Figure 2).
Figure 2—Connexin-40 and Connexin-43. Immunofluorescent staining of mouse heart atrium using Mouse anticonnexin-43 antibody (red) and Mouse anti-connexin-40 antibody (green). Image courtesy of James I. Nagy, PhD, University of Manitoba, Canada.
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Tight junctions barriers that regulate paracellular movements of solutes down their electro-osmotic gradients. They also act as a fence that maintains differential composition of basolateral and apical membrane domains, limiting diffusion of lipids and proteins between cellular compartments . The main components of TJs are claudins, occludins, and junctional adhesion molecules (JAMs). Proteins such as ZO-1, ZO-2, ZO-3, MUPP-1, and PATJ colocalize with claudin proteins and together form tight junctions (Figure 3).
|Figure 3—Claudin proteins. Immunofluorescence staining of frozen mouse jejunum tissue using Mouse anti-Claudin-1 (red), and Mouse anti ZO-1 is labeled in green; nuclei are stained with DAPI (blue). Image courtesy of Jennifer Holmes and Dr. James Anderson, University of North Carolina at Chapel Hill, NC.|
Adherens junctions are the building blocks of tissue architecture. The main components are cadherins and catenins. These proteins form cell−cell junctions (Figure 4), and can facilitate signaling pathways such as AKT, Wnt, and MAPK to govern morphogenesis, tissue homeostasis, and even intercellular communication . Disruption of AJs promotes tumor cell invasion and metastasis .
|Figure 4—Cell junctions. Immunohistochemistry of mouse hippocampus using AF-6 ABfinity™ Recombinant Rabbit Monoclonal Antibody, at 1 ug/ml. Goat anti Rabbit Alexa Fluor® 488 was used as secondary antibody. Image provided by Jim Nagy, Canada.|
Desmosomes and hemidesmosomes are specialized in cell−cell and cell–extracellular matrix adhesion, respectively . They are important in cytoskeletal organization, cell signaling, and tissue patterning. The main components of desmosomes are cadherins (desmogleins and desmocollins). Hemidesmosomes employ integrins as their primary cell adhesion proteins.