Gap junctions are responsible for the direct coupling of cells that enables intercellular exchange of ions, small metabolites and second messengers. Lens epithelial cells are well coupled (Fig.1a) by connexin (Cx) channels that constitute the structural subunits of gap junctions.1,2 Surprisingly, epithelial cell proliferation during the early postnatal period (Fig.1b) was found to be profoundly...

Connexins are protein subunits that constitute the gap junction channel, a dodecameric channel connecting two neighbouring cells formed by two hexameric hemichannels provided by either cell. The gap junction channel permits intercellular communication by allowing the propagation of the action potential and the transfer of small molecules such as cAMP. Six different gap junctional proteins (conn...

Calcium and calmodulin are implicated in mediating the Ca-dependent regulation of gap junctions that are essential for the intercellular transmission of molecules such as nutrients, metabolites, metal ions and signal messengers (< 1000 Da) through its specialized cell membrane channels and communication to extracellular environment. To understand the key determinants for calcium and calmodulin ...

Gap junctions (GJ) provide intercellular communication in all multicellular animal species, being as evolutionary distant as worm and men. In the traditional view GJs are known as specialized cell junctions forming communicating channels connecting the cytoplasm of adjacent cells. In almost all tissues GJ coupled cells can rapidly exchange ions, nutrients, or small metabolites to establish elec...

PURPOSE To investigate the role of the gap junction protein connexin43 (Cx43), which is predominantly expressed in lens epithelial cells in the control of lens development and organization. METHODS Newborn mice in which the Cx43 gene was disrupted by homologous recombination were used. Lenses from Cx43 (-/-) mice and wild-type littermates were processed by using 2% glutaraldehyde fixation for...

Three connexin genes have been reported to be expressed in the lens. The a1 connexin (Cx43) has been detected in mouse lens epithelial cells (Yancey et al., Xiaohua Gong,* En Li,† George Klier,* Qingling Huang,‡ Ying Wu,* Hong Lei,† Nalin M. Kumar,* Joseph Horwitz,‡ and Norton B. Gilula*§ 1992). Both a3 (Cx46) and a8 (Cx50) connexin have been detected in the elongating primary fibers, as well a...

The three connexins expressed in the ocular lens each contain PDZ domain-binding motifs directing a physical association with the scaffolding protein ZO-1, but the significance of the interaction is unknown. We found that Cx50 with PDZ-binding motif mutations did not form gap junction plaques or induce cell-cell communication in HeLa cells, whereas the addition of a seven-amino acid PDZ-binding...

Intercellular communication via gap junctions is thought to play an important role in embryonic cell survival and differentiation. Classical studies demonstrated both dye and electrical coupling of cells in the inner cell mass of mouse embryos, as well as the development of restrictions against coupling between cells of the inner cell mass and surrounding trophectoderm. Here we demonstrate exte...

Exposure to oxidative stress leads to accumulation of reactive oxygen species and this stimulates protective cellular functions as a compensatory response to prevent the spread of apoptotic signal and prevent cell death. The purpose of this dissertation is to understand the importance of PKCγ activation and regulation of the retinal gap junction protein Cx50, and what role PKCγ plays in this ne...

Although congenital heart disease (CHD) is frequently associated with syndromes that affect multiple organs, the majority of cases present as isolated CHD, and typically defects are limited to a defined structure, suggesting a unique developmental mechanism. Despite the frequent occurrence of CHD, relatively few causative genes have been clearly identified (see review1). In this issue of Circul...