Hello ,

The features of Gap Junction is as follows :

1. It permits substances to pass between cells without entering extracellular fluid
2. Are composed entirely of integral membrane protein called connexons
3. Each connexons are made up of six protein subunit called connexins
4. These gap junctions are present in abundant amount in cardiac muscles which are called intercalated discs
5. Because of this gap junction cardiac muscle works as a single functional syncytium
6. Gap junctions are also present in single unit smooth muscles which are present in visceral organs
7. Mutations in connexin leads to many human disease namely X-linked Charcot Marie tooth disease, Clouston syndrome, Cataract, atrial fibrillation and congenital sensorineural hearing loss.

Hello Aspirant,

Gap Junctions allow the exchange of ions, second messengers, and small metabolites between adjacent cells and are formed by two unrelated protien families, the pannexins and connexins. These are highly specialized membrane structures that contain clusters of channels.

Hope this answer clears your doubt.

Thank you!