GapJunctionKanäle

Gap junctions are protein-based channels that form intercellular connections between adjacent cells. These channels are composed of connexins, which are integral membrane proteins that assemble into hexameric structures called connexons. Two connexons, one from each of the adjacent cells, dock together to form a complete gap junction channel. This structure allows for the direct passage of ions and small molecules, such as metabolites and second messengers, from the cytoplasm of one cell to the cytoplasm of another. This direct communication is crucial for coordinating cellular activities within tissues and organs.

The flow of substances through gap junctions is bidirectional and can be regulated by various factors, including changes in intracellular pH, calcium concentration, and phosphorylation. This regulation allows cells to control the extent of their coupling and to respond to different physiological conditions. Gap junctions play vital roles in numerous biological processes, including electrical impulse propagation in the heart and nervous system, the coordinated contraction of smooth muscle, and the synchronization of neuronal activity in the brain. They are also involved in developmental processes and tissue repair. Disruptions in gap junction function have been linked to various diseases, including certain types of cancer, heart conditions, and neurological disorders, highlighting their essential role in maintaining cellular and tissue homeostasis.