connexin complex

Definition

Target type: cellularcomponent

An assembly of six molecules of connexin, made in the Golgi apparatus and subsequently transported to the plasma membrane, where docking of two connexons on apposed plasma membranes across the extracellular space forms a gap junction. [PMID:11146276]

Connexin complexes are integral membrane proteins that form gap junctions, specialized intercellular channels that directly connect the cytoplasm of adjacent cells. They are composed of connexins, a family of transmembrane proteins that assemble into hexameric structures called connexons. These connexons from adjacent cells dock together to form the gap junction channel.

The cellular component of a connexin complex can be described as follows:

- **Transmembrane Domains:** Each connexin molecule has four transmembrane domains that span the cell membrane. These domains are responsible for anchoring the protein within the membrane and creating the channel pore.
- **Cytoplasmic Loops:** Connexins have two cytoplasmic loops, one between the first and second transmembrane domains (loop 1) and another between the third and fourth transmembrane domains (loop 2). These loops play crucial roles in regulating channel gating and interactions with other intracellular proteins.
- **Extracellular Domains:** The extracellular domains of connexins interact with the extracellular domains of connexins from neighboring cells to form the intercellular channel. They are responsible for cell adhesion and channel specificity.
- **Cytoplasmic Tail:** The cytoplasmic tail of connexins is located at the cytoplasmic end of the protein. It interacts with various intracellular proteins involved in channel regulation, trafficking, and anchoring.
- **Connexon:** Six connexin molecules assemble into a hexameric structure called a connexon. Each connexon forms half of the gap junction channel.
- **Gap Junction Channel:** Two connexons from adjacent cells dock together to form the complete gap junction channel. This channel allows for the passage of small molecules and ions between the cytoplasm of the connected cells.

Overall, the cellular component of a connexin complex is a complex and dynamic structure that plays a crucial role in cell-cell communication and tissue homeostasis.'
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Proteins (2)

Compounds (1)