Osmotically Sensitive TREK Channels in Rat Articular Chondrocytes: Expression and Functional Role.

Articular chondrocytes are the primary cells responsible for maintaining the integrity and functionality of articular cartilage, which is essential for smooth joint movement. A key aspect of their role involves mechanosensitive ion channels, which allow chondrocytes to detect and respond to mechanical forces encountered during joint activity; nonetheless, the variety of mechanosensitive ion channels involved in this process has not been fully resolved so far. Because some members of the two-pore domain potassium (K2P) channel family have been described as mechanosensors in other cell types, in this study, we investigate whether articular chondrocytes express such channels.

Ouabain's Influence on TRPV4 Channels of Epithelial Cells: An Exploration of TRPV4 Activity, Expression, and Signaling Pathways.

Ouabain, a substance originally obtained from plants, is now classified as a hormone because it is produced endogenously in certain animals, including humans. However, its precise effects on the body remain largely unknown. Previous studies have shown that ouabain can influence the phenotype of epithelial cells by affecting the expression of cell-cell molecular components and voltage-gated potassium channels.

The β-Subunit (AMOG) of Human Na, K-ATPase Is a Homophilic Adhesion Molecule.

The β subunit of Na, K-ATPase was originally identified as the adhesion molecule on glia (AMOG) that mediates the adhesion of astrocytes to neurons in the central nervous system and that is implicated in the regulation of neurite outgrowth and neuronal migration. While β isoform have been shown to trans-interact in a species-specific mode with the β subunit on the epithelial neighboring cell, the β subunit has been shown to act as a recognition molecule on the glia. Nevertheless, none of the works have identified the binding partner of β or described its adhesion mechanism.

E7 oncoprotein from human papillomavirus 16 alters claudins expression and the sealing of epithelial tight junctions.

Tight junctions (TJs) are cell‑cell adhesion structures frequently altered by oncogenic transformation. In the present study the role of human papillomavirus (HPV) 16 E7 oncoprotein on the sealing of TJs was investigated and also the expression level of claudins in mouse cervix and in epithelial Madin‑Darby Canine Kidney (MDCK) cells. It was found that there was reduced expression of claudins ‑1 and ‑10 in the cervix of 7‑month‑old transgenic K14E7 mice treated with 17β‑estradiol (E2), with invasive cancer.

A Model for the Homotypic Interaction between Na,K-ATPase β Subunits Reveals the Role of Extracellular Residues 221-229 in Its Ig-Like Domain.

The Na, K-ATPase transports Na and K across the membrane of all animal cells. In addition to its ion transporting function, the Na, K-ATPase acts as a homotypic epithelial cell adhesion molecule via its β subunit. The extracellular region of the Na, K-ATPase β subunit includes a single globular immunoglobulin-like domain.

Ouabain Enhances Cell-Cell Adhesion Mediated by β Subunits of the Na,K-ATPase in CHO Fibroblasts.

Adhesion is a crucial characteristic of epithelial cells to form barriers to pathogens and toxic substances from the environment. Epithelial cells attach to each other using intercellular junctions on the lateral membrane, including tight and adherent junctions, as well as the Na,K-ATPase. Our group has shown that non-adherent chinese hamster ovary (CHO) cells transfected with the canine β subunit become adhesive, and those homotypic interactions amongst β subunits of the Na,K-ATPase occur between neighboring epithelial cells.

E-Cadherin and tight junctions between epithelial cells of different animal species.

The assembly and permanent sealing of tight junctions (TJs) depend crucially on cell-cell contacts containing E-cadherin. This poses a puzzling problem because, while TJs can be established between epithelial cells from different tissues and even different animal species ("heterotypic TJs"; Gonzalez-Mariscal et al. 1989, J Membr Biol 107:43), the cell-cell binding mediated by E-cadherin is a highly specific one (Takeichi 1995, Curr Opin Cell Biol 7:619).