establishment of epithelial cell polarity

Definition

Target type: biologicalprocess

The specification and formation of anisotropic intracellular organization of an epithelial cell. [GOC:ascb_2009, GOC:dph, GOC:tb]

Epithelial cell polarity is a fundamental process that establishes the distinct apical and basolateral domains of epithelial cells, crucial for their proper function. This process is initiated during development and maintained throughout the life of the organism. It involves a complex interplay of signaling pathways, cytoskeletal rearrangements, and the trafficking of specific proteins to their correct locations within the cell.

The establishment of epithelial cell polarity begins with the formation of apical-basal axis, which involves the polarization of the cytoskeleton. This involves the assembly of microtubules and actin filaments, which are responsible for transporting vesicles and anchoring proteins to specific locations within the cell. Microtubules play a crucial role in establishing the apical-basal axis, while actin filaments are involved in forming tight junctions and adherens junctions, which seal the apical domain and connect adjacent cells, respectively.

Once the apical-basal axis is established, the cell begins to sort proteins to their respective domains. This sorting process is mediated by a variety of signaling pathways, including the Par complex, Crumbs complex, and Scribble complex. These complexes function as molecular switches, controlling the distribution of proteins to the apical and basolateral domains.

The Par complex, composed of Par3, Par6, and atypical protein kinase C (aPKC), localizes to the apical domain and plays a key role in the establishment of apical polarity. It promotes the recruitment of apical proteins, such as the transmembrane protein Crumbs, and restricts the localization of basolateral proteins.

The Crumbs complex, composed of Crumbs, Stardust, and Pals1, is also localized to the apical domain and functions in maintaining apical polarity. It interacts with the Par complex and plays a role in regulating the trafficking of apical proteins.

The Scribble complex, composed of Scribble, Discs large (Dlg), and Lethal giant larvae (Lgl), localizes to the basolateral domain and functions in establishing and maintaining basolateral polarity. It inhibits the localization of apical proteins to the basolateral domain and promotes the recruitment of basolateral proteins.

The trafficking of proteins to their correct locations is mediated by the endocytic and exocytic pathways. These pathways involve the sorting and packaging of proteins into vesicles, which are then transported to their target domains. The proper sorting and trafficking of proteins are essential for maintaining epithelial cell polarity.

In addition to these core signaling pathways and trafficking mechanisms, other factors, including cell-cell interactions, cell-matrix interactions, and extracellular matrix cues, contribute to the establishment and maintenance of epithelial cell polarity.

Epithelial cell polarity is crucial for a wide range of functions, including barrier formation, selective transport, and cell signaling. Defects in epithelial cell polarity are implicated in a variety of diseases, including cancer, developmental disorders, and inflammatory diseases.'
"

Proteins (1)

Compounds (5)