title: Epithelial homeostasis.
abstract: Epithelia form intelligent, dynamic barriers between the external environment and an organism's interior. Intercellular cadherin-based adhesions adapt and respond to mechanical forces and cell density, while tight junctions flexibly control diffusion both within the plasma membrane and between adjacent cells. Epithelial integrity and homeostasis are of central importance to survival, and mechanisms have evolved to ensure these processes are maintained during growth and in response to damage. For instance, cell competition surveys the fitness of cells within epithelia and removes the less fit; extrusion or delamination can remove apoptotic or defective cells from the epithelial sheet and can restore homeostasis when an epithelial layer becomes too crowded; spindle orientation ensures two-dimensional growth in simple epithelia and controls stratification in complex epithelia; and transition to a mesenchymal phenotype enables active escape from an epithelial layer. This review will discuss these various mechanisms and consider how they are subverted in disease.
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA. Electronic address: ian.g.macara@vanderbilt.edu.
authors.forename: Ian G
authors.initials: IG
authors.lastname: Macara
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Guyer
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Graham
authors.initials: G
authors.lastname: Richardson
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Huo
authors.affiliation: Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Syed M
authors.initials: SM
authors.lastname: Ahmed
mesh_terms: D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism; D004058:Diffusion; D004847:Epithelial Cells / Q000378:metabolism*; D004848:Epithelium / Q000254:growth & development / Q000502:physiology*; D006706:Homeostasis; D006801:Humans; D019108:Tight Junctions / Q000378:metabolism
chemical_list: D015820:Cadherins