What is the function of connexin 43?
Normal Function The GJA1 gene provides instructions for making a protein called connexin 43, which is one of 21 connexin proteins. Connexins play a role in cell-to-cell communication by forming channels, or gap junctions, between cells.
Are gap junctions integral proteins?
Gap junctions are aggregates of intercellular channels that permit direct cell–cell transfer of ions and small molecules. Gap-junctional channels are composed of hexamers of medium-sized families of integral proteins: connexins in chordates and innexins in precordates.
Do all cells have gap junctions?
Gap junctions are analogous to the plasmodesmata that join plant cells. Gap junctions occur in virtually all tissues of the body, with the exception of adult fully developed skeletal muscle and mobile cell types such as sperm or erythrocytes.
What does a gap junction do?
Gap junctions are channels that physically connect adjacent cells, mediating the rapid exchange of small molecules, and playing an essential role in a wide range of physiological processes in nearly every system in the body, including the nervous system.
What are the two types of connexon?
Connexons made of the same type of connexins are considered homomeric, while connexons made of differing types of connexins are heteromeric.
How many helical subunits does a connexin have?
The hemichannel is made of six connexin subunits, each of which consist of four transmembrane segments….
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What proteins make up gap junctions?
Gap junctions form channels between adjacent cells. The core proteins of these channels are the connexins. Regulation of gap junction communication (GJC) can be modulated by connexin-associating proteins, such as regulatory protein phosphatases and protein kinases, of which c-Src is the best-studied.
Is a synapse a gap junction?
Electrical Synapses. Electrical synapses are gap junctions. When present between neurons, they are very different from chemical synapses where the separateness of the cells is not in question. They allow the direct spread of current from one cell to another, without delay or need for receptor and decoding systems.
What is connexin 43 (Cx43)?
Connexin 43 (Cx43) is a member of the large family of gap junction proteins. Connexins assemble as a hexamer and are transported to the plasma membrane to create a hemichannel that can associate with hemichannels on nearby cells to create cell-to-cell channels. Clusters of these channels assemble to make gap junctions.
What does Cx43 stand for?
The gap junction protein connexin43 (Cx43) is widely expressed in mammalian cells and forms intercellular channels for the transfer of small molecules between adjacent cells, as well as hemichannels that mediate bidirectional transport of molecules between the cell and the surrounding environment. C …
What is the C-terminus of Cx43 made of?
The Cx43 C-terminus contains a phosphorylation-dependent 14-3-3 binding motif at Serine 373 (within 10 amino acids of the end of the protein). 14-3-3 proteins are known to regulate protein transport and have been implicated in facilitating de novo Cx43 transport from ER to Golgi apparatus [130, 131].
Why is Cx43 phosphorylated by PKC?
Phosphorylation of Cx43 is important in regulating assembly and function of gap junctions. Ser368 of Cx43 is phosphorylated by protein kinase C (PKC) after activation by phorbol esters, which decreases cell-to-cell communication. Src can interact with and phosphorylate Cx43 to alter gap junction communication.