Revista de Morfología y Anatomía

Cell-Cell Junctions and Epithelial Differentiation

Abstract

Ramena Yathish, Ramena Grace

Epithelial tissues make up most organs in the body and perform various functions like protection, excretion, secretion etc. The epithelial tissues consist of different cell type like squamous, cuboidal, glandular and columnar depending on the organ and function. These cells can be of single or multiple layers. The epithelial cells are tightly packed together and connected by junctional complexes. They are tight junctions, adherens junctions, gap junctions, desmosomes and hemi desmosomes. These junctional complexes are made up of trans-membrane proteins that form homo or hetero complexes. The proteins expressed at the cell-cell junctions act as binding docks for various adaptor molecules at their c-terminus and there regulate cell signaling. Some junctional molecules connect to cell cytoskeleton and basement membrane and maintain epithelial integrity, cell polarity and epithelial differentiation. Any dysregulation of cell-cell junctional molecules due to pathogenic conditions results in loss of epithelial integrity and differentiation leading the cells to undergo EMT.