XXXX integrins in epithelial tissues: a unique distribution in the lens.

@entity10483 @entity6927 @entity2393 @entity989
Integrins have been shown to play a role in directing and maintaining cell differentiation and polarization. The embryonic lens provides a good system in which to examine their role in epithelial cell differentiation, because all stages of lens development are represented in an individual embryonic lens. Therefore, we examined the expression and distribution of @entity2393 heterodimers in both the lens epithelium and the differentiated lens fiber cells. In lens epithelial cells @entity2393 was found to be localized to all membrane surfaces. Lens fiber cells contained @entity2393 all along their lateral borders as well as at the site of their attachment to the lens capsule and at their interface with lens epithelial cells. The distribution of @entity2393 in the lens was distinct from that observed in simple epithelia, the @entity989 ( @entity989 ), kidney, and intestine, where it was limited to a basal lateral localization. We examined the specific @entity2393 heterodimers expressed in the lens by Western blot analysis for the integrin alpha subunits following @entity10483 immunoprecipitation and compared them with those expressed in @entity989 cells. In the lens we detected alpha 3 and alpha 6 subunits but not @entity6927 , alpha 5, or alpha v. When the lens was separated into epithelial and fiber cells, we found that alpha 3 was expressed at a higher level in the epithelial cells, while alpha 6 was primarily associated with the fiber cells. In the @entity989 the primary @entity2393 detected was alpha 3. Unlike in lens and kidney, alpha 6 @entity10483 integrin in @entity989 cells was expressed only at a low level. alpha v was also expressed in @entity989 cells but not as a @entity10483 heterodimer. As in the lens, neither alpha 5 @entity10483 nor @entity6927 @entity10483 integrin was detected in @entity989 . Both lens and @entity989 cells express a specific subset of @entity2393 heterodimers which are likely to be important to the initiation and maintenance of their differentiated phenotype.
