Cell polarity is a feature of most cells including epithelial cells. All epithelial cells are polarized along their apical basal axis, whereas some are also polarized along the plane of the epithelial sheet, a feature called planar cell polarity as opposed to apical basal polarity that is seen in all epithelial cells. Apical basal polarity is critical for epithelial cells to form sheets, change their shape to form tissues and organs, and to function normally. One important problem we study are the mechanisms of how epithelial cells polarize and maintain their polar architecture.
Cell polarity and epithelial cells
Cells express polarity by displaying different plasma membrane domains. Simple polarized cells have two membrane domains whereas in more complex polarized cells, such as epithelial cells or photoreceptor cells, multiple membrane domains are found.
Further readings:
Furuse M, Tsukita S. (2006). Claudins in occluding junctions of humans and flies. Trends Cell Biol. 16:181-8.
Anderson JM, Van Itallie CM, Fanning AS. (2004). Setting up a selective barrier at the apical junction complex. Curr Opin Cell Biol. 16:140-5.
Tepass U. (2003). Claudin complexities at the apical junctional complex. Nat Cell Biol. 5:595-7.
Nelson WJ. (2003). Adaptation of core mechanisms to generate cell polarity. Nature 422:766-74.
Knust E, Bossinger O. (2002). Composition and formation of intercellular junctions in epithelial cells. Science 298, 56:1955-9.
Tepass U, Tanentzapf G, Ward R, Fehon R. (2001) Epithelial cell polarity and cell junctions in Drosophila. Annu Rev Genet. 35:747-84.
The apical junctional complex is a key structure in the organization of epithelial polarity. It forms a belt around the apical pole of epithelial cells and segregates apical from basolateral membrane domains. The apical junctional complex of most epithelial cells is composed of an adherens junction, the zonula adherens, and a second junction that regulates the diffusion of material across the epithelial sheet through the space between cells (the paracellular space). This so-called occluding junction is the tight junction in chordate animals including humans and the septate junction in epithelia of all other non-chordate animals such as Drosophila.
The apical junctional complex in chordates and Drosophila (and other non-chordate animals).
This and the linked pages will briefly discuss our research program organized as several topics. On this page we will discuss Cell Polarity and Epithelial Cells. For other topics click on the links to the right. As we go along we will introduce a number of genes and their encoded proteins that we work on and are required for cell polarity, cell adhesion and morphogenesis such as Crumbs, Yurt, Cdc42, DE-cadherin, alpha-catenin and Eyes shut.
Tepasslab: Research
Cell Polarity and Epithelial Cells (this page)
Epithelial Morphogenesis
Photoreceptor Cells
Cancer and Blindness
Our research in funded through contributions from the following agencies:
The Canadian Institutes for Health Research (CIHR)
The Natural Sciences and Engineering Research Council of Canada (NSERC)
The Canadian Cancer Society (CCS) through the National Cancer Institute of Canada (NCIC)
The Foundation for Fighting Blindness (FFB)