title: Differentiation of columnar epithelia: the hensin pathway.
abstract: Epithelia, the most common variety of cells in complex organisms exist in many shapes. They are sheets of polarized cells that separate two compartments and selectively transport materials from one to the other. After acquiring these general characteristics, they differentiate to become specialized types such as squamous columnar or transitional epithelia. High density seeding converts a kidney-derived cell line from flat ;generic' epithelial cells to columnar cells. The cells acquire all the characteristics of differentiated columnar cells, including microvilli, and the capacity for apical endocytosis. The high seeding density induces the deposition of a new protein termed hensin and polymerization of hensin is the crucial event that dictates changes in epithelial phenotype. Hensin is widely expressed in most epithelia. Its deletion in mice leads to embryonic lethality at the time of generation of the first columnar epithelium, the visceral endoderm. Moreover many human cancers have deletions in the hensin gene, which indicates that it is a tumor suppressor.
authors.affiliation: Department of Medicine, College of Physicians and Surgeons of Columbia University, 630 W 168th St, New York, NY 10032, USA.
authors.forename: Soundarapandian
authors.initials: S
authors.lastname: Vijayakumar
authors.forename: Jiro
authors.initials: J
authors.lastname: Takito
authors.forename: XiaoBo
authors.initials: X
authors.lastname: Gao
authors.forename: George J
authors.initials: GJ
authors.lastname: Schwartz
authors.forename: Qais
authors.initials: Q
authors.lastname: Al-Awqati
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins; D002454:Cell Differentiation / Q000502:physiology*; D004268:DNA-Binding Proteins; D047108:Embryonic Development / Q000235:genetics; D004847:Epithelial Cells / Q000166:cytology*; D006801:Humans; D007668:Kidney / Q000166:cytology; D008954:Models, Biological; D009077:Mucins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009369:Neoplasms / Q000235:genetics; D011108:Polymers; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins
chemical_list: D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; C114202:Dmbt1 protein, mouse; D009077:Mucins; D011108:Polymers; D025521:Tumor Suppressor Proteins