Biomaterial Database

Developmental regulation of gap junctions and their role in mammary epithelial cell differentiation. 2003

Marwan E El-Sabban, and Lina F Abi-Mosleh, and Rabih S Talhouk

Department of Human Morphology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. me00@aub.edu.lb

Gap junctions play a critical role in the development and differentiation of many tissues. Formed by the joining of two connexons on opposing membranes of two cells, gap junctions permit passage of ions and small molecules. Six connexins (Cx) belonging to a family of closely related tetraspan transmembrane proteins form a connexon. Connexin expression peaks in lactation, and those identified in the gland, thus far, are Cx26, Cx30, Cx32, and Cx43. Cx43 associates with myoepithelial cells, while others associate with epithelial and ductular cells. In vitro, assembly of functional gap junctions appears to be essential for differentiation of mammary epithelial cells. However, the role of gap junction intercellular communication (GJIC) in differentiation and growth remains unclear. Recent evidence challenges the view that gap junctions are simply pore-forming proteins and suggests that cell adhesion-associated proteins interact with the cytosolic carboxy-terminus of connexins and participate in signaling events. The possible implications on mammary cell function are discussed.

UI	MeSH Term	Description	Entries
D008321	Mammary Glands, Animal	MAMMARY GLANDS in the non-human MAMMALS.	Mammae,Udder,Animal Mammary Glands,Animal Mammary Gland,Mammary Gland, Animal,Udders
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D004847	Epithelial Cells	Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.	Adenomatous Epithelial Cells,Columnar Glandular Epithelial Cells,Cuboidal Glandular Epithelial Cells,Glandular Epithelial Cells,Squamous Cells,Squamous Epithelial Cells,Transitional Epithelial Cells,Adenomatous Epithelial Cell,Cell, Adenomatous Epithelial,Cell, Epithelial,Cell, Glandular Epithelial,Cell, Squamous,Cell, Squamous Epithelial,Cell, Transitional Epithelial,Cells, Adenomatous Epithelial,Cells, Epithelial,Cells, Glandular Epithelial,Cells, Squamous,Cells, Squamous Epithelial,Cells, Transitional Epithelial,Epithelial Cell,Epithelial Cell, Adenomatous,Epithelial Cell, Glandular,Epithelial Cell, Squamous,Epithelial Cell, Transitional,Epithelial Cells, Adenomatous,Epithelial Cells, Glandular,Epithelial Cells, Squamous,Epithelial Cells, Transitional,Glandular Epithelial Cell,Squamous Cell,Squamous Epithelial Cell,Transitional Epithelial Cell
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000072259	Connexin 26	A gap junction protein encoded by the Gap Junction Beta 2 or GJB2 gene. In the cochlea and epidermis, its hexamers form channels between cells that open to allow cell-to-cell diffusion of small molecules as well as recycling of potassium. Mutations in Connexin 26 are associated with congenital SENSORINEURAL HEARING LOSS.	Connexin Cx26,Connexin beta-2,Gap Junction beta-2 protein,beta2 Connexin,26, Connexin,Connexin beta 2,Connexin, beta2,Cx26, Connexin,Gap Junction beta 2 protein,beta-2, Connexin
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D017629	Gap Junctions	Connections between cells which allow passage of small molecules and electric current. Gap junctions were first described anatomically as regions of close apposition between cells with a narrow (1-2 nm) gap between cell membranes. The variety in the properties of gap junctions is reflected in the number of CONNEXINS, the family of proteins which form the junctions.	Gap Junction,Junction, Gap,Junctions, Gap
D017630	Connexins	A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.	Connexin,Connexin Complex Proteins,Gap Junction Proteins,Gap Junction Channel Proteins,Gap Junction Protein,Junction Protein, Gap,Junction Proteins, Gap
D042361	Mammary Glands, Human	Glandular tissue in the BREAST of human that is under the influence of hormones such as ESTROGENS; PROGESTINS; and PROLACTIN. In WOMEN, after PARTURITION, the mammary glands secrete milk (MILK, HUMAN) for the nourishment of the young.	Human Mammary Gland,Human Mammary Glands,Mammary Alveoli, Human,Mammary Ducts, Human,Mammary Epithelia, Human,Mammary Epithelium, Human,Mammary Gland,Mammary Glands,Mammary Lobules, Human,Alveoli, Human Mammary,Alveolus, Human Mammary,Duct, Human Mammary,Ducts, Human Mammary,Epithelia, Human Mammary,Epithelium, Human Mammary,Gland, Human Mammary,Gland, Mammary,Glands, Human Mammary,Glands, Mammary,Human Mammary Alveoli,Human Mammary Alveolus,Human Mammary Duct,Human Mammary Ducts,Human Mammary Epithelia,Human Mammary Epithelium,Human Mammary Lobule,Human Mammary Lobules,Mammary Alveolus, Human,Mammary Duct, Human,Mammary Gland, Human,Mammary Lobule, Human