The presentation covers the structure and function of gap junctions, specialized intercellular junctions that facilitate direct communication and fast transport of ions and metabolites between cells. It highlights the role of connexons, the regulation of gap junction permeability, and their importance in electrical signaling in neurons and coordinated contraction in cardiomyocytes. Additionally, it discusses the clinical implications of mutations in connexin genes, which can lead to various disorders including arrhythmogenic right ventricular cardiomyopathy.

1. Presentat
ion on :
JUNCTIONS
Guided by : Dr. Sukanta Das
Prepared by : Sagnik Dandapat
Id: 63/2022

2. • Specialized intercellular junction
that enables direct communication
• Less selective and faster transport
(ions : Sodium, Potassium, Calcium
metabolites : glucose, amino acids,
nucleotides
second messenger : cAMP, IP3 )
• electrical synapse or NEXUS

3. • Specialized intercellular junction
that enables direct communication
• Less selective and faster transport
(ions : Sodium, Potassium, Calcium
metabolites : glucose, amino acids,
nucleotides
second messenger : cAMP, IP3 )
• electrical synapse or NEXUS
sharing is caring !

4. Structure

5. Connexons:
• Binding block of gap junctions
• Hexameric complex formed by the assembly of six
connexin protein subunits

6. Connexon Channels :
• Half-Half contribution of connexons
• Two adjacent cells align their connexons [Docking]

7. Regulation of the Gap Junction :
• Calcium ion & Hydrogen ion concentration
• Increase in Calcium concentration can
increase the permeability of the channel
(shutter mechanism)
• Acidification increases permiability

8. Gap Junction Mobility :
• Can diffuse laterally within the cell membrane
• By endocytosis & exocytosis
• Cytoskeletal interactions
Essential for maintaining proper cell-to-cell
communication and coordinating cellular activities

9. Functions
• Direct intercellular communication

10. Functions
• Rapid transfer of electrical signals between neurons
( Electrical Synapse)

11. Functions
• Rapid transfer of electrical signals between neurons
( Electrical Synapse)

12. Functions
• Rapid transfer of electrical signals between neurons
( Electrical Synapse)

13. Functions
• Coordinated contraction in Cardiomyocytes

14. Functions
Intercalated discs
• Coordinated contraction in Cardiomyocytes
Gap junction

15. Functions
SA node
Coordinated contraction of entire myocardium as a functional syncytium

16. Clinical Importance
• Tissue and organ function
• Embryonic development
• Neurological disorders
• Cardiac arrhythmias
Mutation in connexin genes can result in conditions like
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

17. Clinical Importance
• Tissue and organ function
• Embryonic development
• Neurological disorders
• Cardiac arrhythmias
Mutation in connexin genes can result in conditions like
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

18. THANK YOU
.