Gap junctions

Definition

Gap junctions are specialized intercellular connections that directly connect the cytoplasm of two cells, allowing for the transfer of ions, molecules, and electrical impulses. They play a crucial role in cell communication and coordination within tissues.

5 Must Know Facts For Your Next Test

1. Gap junctions are formed by connexin proteins that assemble into connexons.
2. Each gap junction channel allows passage of molecules up to approximately 1 kDa in size.
3. They are essential for maintaining homeostasis in various tissues, including cardiac and nervous tissue.
4. Gap junctions can be regulated by factors such as pH, calcium concentration, and phosphorylation.
5. Mutations or malfunctions in gap junctions can lead to diseases like cardiac arrhythmias and certain neuropathies.

Review Questions

• What types of molecules can pass through gap junctions?
• Which proteins are primarily involved in the formation of gap junctions?
• How can the function of gap junctions be regulated?

Related terms

Connexin: Connexins are a family of structurally related transmembrane proteins that form the channels in gap junctions.

Desmosomes: Desmosomes are adhesive intercellular junctions that provide strong adhesion between cells but do not allow molecular transfer.

Tight Junctions: Tight junctions create a nearly impermeable barrier between adjacent cells preventing leakage of materials through the space between cells.