Do connexin proteins form gap junctions?
Connexins are a family of at least 15 proteins that form intercellular membrane channels of gap junctions and allow diffusional movement of ions, metabolites, and potential signaling molecules. These structural molecules play important roles in bidirectional communication between the oocyte and granulosa cells.
How are gap junctions formed?
Gap junctions are formed by head to head docking of hexameric assemblies (connexons) of tetraspan integral membrane proteins, the connexins. these channels cluster into polymorphic maculae or plaques containing a few to thousands of units.
What are tight junctions made of?
Tight junctions are composed of a branching network of sealing strands with each strand acting independently from the others. The major types of proteins in junctions are the claudins and the occludins.
What is the function of connexin?
Connexins are a family of at least 15 proteins that form intercellular membrane channels of gap junctions and allow diffusional movement of ions, metabolites, and potential signaling molecules. These structural molecules play important roles in bi-directional communication between the oocyte and granulosa cells.
What are gap junctions made of?
Gap junctions are plasma membrane spatial microdomains constructed of assemblies of channel proteins called connexins in vertebrates and innexins in invertebrates. The channels provide direct intercellular communication pathways allowing rapid exchange of ions and metabolites up to approximately 1 kD in size.
What is gap junction proteins?
Gap junctions are specialized intercellular connections between a multitude of animal cell-types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.
What proteins are found in tight junctions?
Tight junction complex is composed of occludin and claudin proteins, adhesion junctions (integral membrane-bound cadherins and cytoplasmic accessory proteins, i.e., α and β catenin), JAM-1, and accessory proteins (ZO-1, ZO-2, ZO-3).
What are the two major proteins that comprise tight junctions?
Tight junctions contain two types of transmembrane proteins, occludins and claudins, which confer these functions (Fig. 3), and associated cytoplasmic proteins (Fig. 4) that may link tight junctions to the actin-cytoskeleton and the adherens junction.